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SEASIDE    STUDIES 


NATURAL    HISTORY, 


BY 


ELIZABETH    C.   AGASSIZ 

AND 

ALEXANDER    AGASSIZ. 


MARINE  ANIMALS  OF  MASSACHUSETTS  BAY, 
RADIATES. 


BOSTON: 
TICK  NOR     AND     FIELDS. 

1865. 


5 

o 


Entered  according  to  Act  of  Congress,  in  the  year  1865.  by 

ALEXANDER     AGAS8IZ, 
in  the  Clerk's  Office  of  the  District  Court  for  the  District  of  Massachusetts. 


UNIVERSITY  PRESS: 

WELCH,   BIG  BLOW,    AND   COMPANY, 

CAMBRIDGE. 


THIS   LITTLE  BOOK 

IS  AFFECTIONATELY   DEDICATED   BY  THE   AUTHORS    TO 

PROFESSOR    L.    AGASSIZ, 

WHOSE   PRINCIPLES    OF    CLASSIFICATION    HAVE   BEEN   THE   MAIN 
GUIDE   IN    ITS    PREPARATION. 


PREFACE. 


THIS  volume  is  published  with  the  hope  of  supplying 
a  want  often  expressed  for  some  seaside  book  of  a  popu 
lar  character,  describing  the  marine  animals  common  to 
our  shores.  There  are  many  English  books  of  this  kind ; 
but  they  relate  chiefly  to  the  animals  of  Great  Britain, 
and  can  only  have  a  general  bearing  on  those  of  our  own 
coast,  which  are  for  the  most  part  specifically  different 
from  their  European  relatives.  While  keeping  this  ob 
ject  in  view,  an  attempt  has  also  been  made  to  present 
the  facts  in  such  a  connection,  with  reference  to  prin 
ciples  of  science  and  to  classification,  as  will  give  it  in 
some  sort  the  character  of  a  manual  of  Natural  History, 
in  the  hope  of  making  it  useful  not  only  to  the  general 
reader,  but  also  to  teachers  and  to  persons  desirous  of 
obtaining  a  more  intimate  knowledge  of  the  subjects 
discussed  in  it.  With  this  purpose,  although  nearly  all 
the  illustrations  are  taken  from  among  the  most  com 
mon  inhabitants  of  our  bay,  a  few  have  been  added 
from  other  localities  in  order  to  fill  out  this  little  sketch 
of  Radiates,  and  render  it,  as  far  as  is  possible  within 
such  limits,  a  complete  picture  of  the  type. 


VI  PREFACE. 

A  few  words  of  explanation  are  necessary  with  ref 
erence  to  the  joint  authorship  of  the  book.  The  draw 
ings  and  the  investigations,  where  they  are  not  referred 
to  other  observers,  have  been  made  by  MR.  A.  AGASSIZ, 
the  illustrations  having  been  taken,  with  very  few  ex 
ceptions,  from  nature,  in  order  to  represent  the  animals, 
as  far  as  possible,  in  their  natural  attitudes ;  and  the 
text  has  been  written  by  MRS.  L.  AGASSIZ,  with  the 
assistance  of  MR.  AGASSIZ'S  notes  and  explanations. 

CAMBRIDGE,  May,  18G5. 


CONTENTS 


PAGE 
ON  RADIATES  IN  GENERAL  .......         1 

GENERAL  SKETCH  OF  THE  POLYPS  ......  5 

ACTINOIDS         ..........  7 

MADREPORIANS      .........  16 

HALCYONOIDS    .         .         .         .         .         .         .         .         .         .19 

GENERAL  SKETCH  OF  ACALEPHS 21 

CTENOPHOR^:     ..........  26 

EMBRYOLOGY  OF  CTENOPHOR.E         ......  34 

DISCOPHOR.E      ..........  37 

HYDROIDS      ..........  49 

MODE  OF  CATCHING  JELLY-FISHES      .         .         .         .         .         .85 

ECHINODERMS          .........  91 

HOLOTHURIANS  ..........  95 

ECHINOIDS     ..........  101 

STAR-FISHES 108 

OPHIURANS    .         .         .         .         .         .         .         .         ...  115 

CRINOIDS  .         .         .         .         .         .         .         .         .         .120 

EMBRYOLOGY  OF  ECHINODERMS         .         .         .         .         .         .  123 

DISTRIBUTION  OF  LIFE  IN  THE  OCEAN           .....  141 

SYSTEMATIC  TABLE         ........  152 

INDEX       .  154 


MARINE  ANIMALS  OF  MASSACHUSETTS  BAY. 


ON  EADIATES  IN   GENERAL. 

IT  is  perhaps  not  strange  that  the  Radiates,  a  type  of  animals 
whose  home  is  in  the  sea,  many  of  whom  are  so  diminutive  in  size, 
and  so  light  and  evanescent  in  substance,  that  they  are  hardly  to 
be  distinguished  from  the  element  in  which  they  live,  should  have 
been  among  the  last  to  attract  the  attention  of  naturalists.  Nei 
ther  is  it  surprising  to  those  who  know  something  of  the  history  of 
these  animals,  that  when  the  investigation  of  their  structure  was 
once  begun,  when  some  insight  was  gained  into  their  complex  life, 
their  association  in  fixed  or  floating  communities,  their  wonder 
ful  processes  of  development  uniting  the  most  dissimilar  individ 
uals  in  one  and  the  same  cycle  of  growth,  their  study  should  have 
become  one  of  the  most  fascinating  pursuits  of  modern  science, 
and  have  engaged  the  attention  of  some  of  the  most  original  in 
vestigators  during  the  last  half  century.  It  is  true  that  from 
the  earliest  days  of  Natural  History,  the  more  conspicuous  and 
easily  accessible  of  these  animals  attracted  notice  and  found  their 
way  into  the  scientific  works  of  the  time.  Even  Aristotle  de 
scribes  some  of  them  under  the  names  of  Acalephae  and  Knidae, 
and  later  observers  have  added  something,  here  and  there,  to  our 
knowledge  on  the  subject ;  but  it  is  only  within  the  last  fifty 
years  that  their  complicated  history  has  been  unravelled,  and  the 
facts  concerning  them  presented  in  their  true  connection. 

Among  the  earlier  writers  on  this  subject  we  are  most  indebted 
to  Rondelet,  in  the  sixteenth  century,  who  includes  some  account 
of  the  Radiates,  in  his  work  on  the  marine  animals  of  the  Medi 
terranean.  His  position  as  Professor  in  the  University  at  Mont- 
i 


Z  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

pelier  gave  him  an  admirable  opportunity,  of  which  he  availed 
himself  to  the  utmost,  for  carrying  out  his  investigations  in  this 
direction.  Seba  and  Klein,  two  naturalists  in  the  North  of  Eu 
rope,  also  published  at  about  this  time  numerous  illustrations  of 
marine  animals,  including  Radiates.  But  in  all  these  works  we 
find  only  drawings  and  descriptions  of  the  animals,  without  any 
attempt  to  classify  them  according  to  common  structural  features. 
In  1776,  0.  F.  Miiller,  in  a  work  on  the  marine  and  terrestrial 
faunae  of  Denmark,  gave  some  admirable  figures  of  Radiates, 
several  of  which  are  identical  with  those  found  on  our  own 
coast.  Cavolini  also  in  his  investigations  on  the  lower  marine 
animals  of  the  Mediterranean,  and  Ellis  in  his  work  upon  those 
of  the  British  coast,  did  much  during  the  latter  half  of  the  past 
century  to  enlarge  our  knowledge  of  them. 

It  was  Cuvier,  however,  who  first  gave  coherence  and  precision 
to  all  previous  investigations  upon  this  subject,  by  showing  that 
these  animals  are  united  on  a  common  plan  of  structure  expres 
sively  designated  by  him  under  the  name  Radiata.  Although, 
from  a  mistaken  appreciation  of  their  affinities,  he  associated 
some  animals  with  them  which  do  not  belong  to  the  type,  and 
have  since,  upon  a  more  intimate  knowledge  of  their  structure, 
been  removed  to  their  true  positions  ;  yet  the  principle  intro 
duced  by  him  into  their  classification,  as  well  as  into  that  of  the 
other  types  of  the  animal  kingdom,  has  been  all  important  to 
science. 

It  was  in  the  early  part  of  this  century  that  the  French  began 
to  associate  scientific  objects  with  their  government  expeditions. 
Scarcely  any  important  voyage  was  undertaken  to  foreign  coun 
tries  by  the  French  navy  which  did  not  include  its  corps  of  nat 
uralists,  under  the  patronage  of  government.  Among  the  most 
beautiful  figures  we  have  of  Radiates,  are  those  made  by  Sa- 
vigny,  one  of  the  French  naturalists  who  accompanied  Napoleon 
to  Egypt ;  and  from  this  time  the  lower  marine  animals  began 
to  be  extensively  collected  and  studied  in  their  living  condition. 
Henceforth  the  number  of  investigators  in  the  field  became  more 
numerous,  and  it  may  not  be  amiss  to  give  here  a  slight  account 
of  the  more  prominent  among  them. 

Darwin's  fascinating  book,  published  after  his  voyage  to  the 


ON    RADIATES    IN    GENERAL.  6 

Pacific,  and  giving  an  account  of  the  Coral  islands,  the  many 
memoirs  of  Milne  Edwards  and  Haime,  and  the  great  works  of 
Quoy  and  Gaimard,  and  of  Dana,  are  the  chief  authorities  upon 
Polyps.  In  the  study  of  the  European  Acalephs  we  have  a  long 
list  of  names  high  in  the  annals  of  science.  Eschscholtz,  Peroii 
and  Lesueur,  .Quoy  and  Gaimard,  Lesson,  Mertens,  and  Huxley, 
have  all  added:  largely  to  our  information  respecting  these  ani 
mals,  their  various  voyages  having  enabled  them  to  extend  their 
investigations  "Over  a  wide  field.  No  less  valuable  have  been  the 
contributions  of  Kolliker,  Leuckart,  Gegenbaur,  and  Yogt,  who 
in  their  frequent  excursions  to  the  coasts  of  Italy  and  France 
have  made  a'  special  study  of  the  Acalephs,  and  whose  descrip 
tions  have  all  the  .'vividness  and  freshness  which  nothing  but 
familiarity  with'  the  living  specimens  can  give.  Besides  these, 
we  have  the  admirable  works  of  Yon  Siebold,  of  Ehrenberg, 
the  great  interpreter  Gf  the  microscopic  world,  of  Steenstrup, 
Dujardin,  Dalyell,  Forbes,  Allman,  and  Sars.  Of  these,  the  four 
latter  were  fortunate  in  having  their  home  on  the  sea-shore  with 
in  reach  of  the  objects  of  their  study,  so  that  they  could  watch 
them  in  their  living  condition,  and  follow  all  their  changes.  The 
charming  books  of  Forbes,  who  knew  so  well  how  to  popularize 
his  instructions,  and i  present  scientific  results  under  the  most  at 
tractive  form,  are  well' known  to  English  readers.  But  a  word  on 
the  investigations  of  Sars  may  not  be  superfluous. 

Born  near  the  coast  of  Norway,  and  in  early  life  associated 
with  the  Church, -his  passion  for  Natural  History  led  him  to  em 
ploy  all  his  spare  time  in  the  study  of  the  marine  animals  im 
mediately  about  him,  and  his  first  papers  on  this  subject  attracted 
so  much  attention,  that  he  was  offered  the  place  of  Professor  at 
Christiania,  and  henceforth  devoted  himself  exclusively  to  scien 
tific  pursuits, \and  especially  to  the  investigation  of  the  Acalephs. 
He  gave  us  the  key  to  the  almost  fabulous  transformations  of 
these  animals,  and  opened  a  new  path  in  science  by  showing  the 
singular  phenomenon  of  the  so-called  "  alternate  generations," 
in, which  the  different  phases  of  the  same  life  may  be  so  distinct 
and  seemingly  so  disconnected  that,  until  we  find  the  relation 
between  them,  we  seem  to  have  several  animals  where  we  have 
but  one. 


4  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

To  the  works  above  mentioned,  we  may  add  the  third  and 
fourth  volumes  of  Professor  Agassiz's  Contributions  to  the  Nat 
ural  History  of  the  United  States,  which  are  entirely  devoted  to 
the  American  Acalephs. 

The  most  important  works  and  memoirs  concerning  the  Echino- 
derms  are  those  by  Klein,  Link,  Johannes  Miiller,  Jiiger.  Des- 
moulins,  Troschel,  Sars,  Savigny,  Forbes,  Agassiz,  and  Lutken, 
but  excepting  those  of  Forbes  and  Sars,  few  of  these  observations 
are  made  upon  the  living  specimens.  It  may  be  well  to  mention 
here,  for  the  benefit  of  those  who  care  to  know  something  more 
of  the  literature  of  this  subject  in  our  own  country,  a  number  of 
memoirs  on  the  Radiates  of  our  coasts,  published  by  the  various 
scientific  societies  of  the  United  States,  and  to  be  found  in  their 
annals.  Such  are  the  papers  of  Gould,  Agassiz,  Leidy,  Stimpson, 
McCrady,  Clark,  A.  Agassiz,  and  Verrill. 

One  additional  word  as  to  the  manner  in  which  the  subjects 
included  in  the  following  descriptions  are  arranged.  We  have 
seen  that  Cuvier  recognized  the  unity  of  plan  in  the  structure 
of  the  whole  type  of  Radiates.  All  these  animals  have  their 
parts  disposed  around  a  common  central  axis,  and  diverging  from 
it  toward  the  periphery.  The  idea  of  bilateral  symmetry,  or  the 
arrangement  of  parts  on  either  side  of  a  longitudinal  axis,  on 
which  all  the  higher  animals  are  built,  does  not  enter  into  their 
structure,  except  in  a  very  subordinate  manner,  hardly  to  be  per 
ceived  by  any  but  the  professional  naturalist.  This  radiate  struc 
ture  being  then  common  to  the  whole  type,  the  animals  compos 
ing  it  appear  under  three  distinct  structural  expressions  of  the 
general  plan,  and  according  to  these  differences  are  divided  into 
three  classes,  —  Polyps,  Acalephs,  and  Echinoderms.  With  these 
few  preliminary  remarks  we  may  now  take  up  in  turn  these  dif- 
erent  groups,  beginning  with  the  lowest,  or  the  Polyps.* 

*  It  is  to  be  regretted  that  on  account  of  the  meagre  representations  of  Polyps  on 
our  coast,  where  the  coral  reefs,  which  include  the  most  interesting  features  of  Polyp 
life,  are  entirely  wanting,  our  account  of  these  animals  is  necessarily  deficient  in  vari 
ety  of  material.  When  we  reach  the  Acalephs  or  Jelly-Fishes,  in  which  the  fauna  of 
our  shores  is  especially  rich,  we  shall  not  have  the  same  apology  for  dulness  ;  and  it 
will  he  our  own  fault  if  our  readers  are  not  attracted  by  the  many  graceful  forms  to 
which  we  shall  then  introduce  them. 


Fig.  i. 


GENERAL  SKETCH  OF  THE  POLYPS. 


GENERAL  SKETCH  OF  THE  POLYPS. 

BEFORE  describing  the  different  kinds  of  Polyps  living  on  our 
immediate  coast,  we  will  say  a  few  words  of  Polyps  in  general 
and  of  the  mode  in  which  the  structural  plan  common  to  all 
Radiates  is  adapted  to  this  particular  class.  In  all  Polyps  the 
body  consists  of  a  sac  divided  by  vertical  partitions  (Fig.  1.)  into 
distinct  cavities  or  chambers.  These  parti- 
tions  are  not,  however,  all  formed  at  once,  but 
are  usually  limited  to  six  at  first,  multiplying 
indefinitely  with  the  growth  of  the  animal  in 
some  kinds,  while  in  others  they  never  in 
crease  beyond  a  certain  definite  number.  In 
the  axis  of  the  sac,  thus  divided,  hangs  a 
smaller  one,  forming  the  digestive  cavity, 
and  supported  for  its  whole  length  by  the  six 
primary  partitions.  The  other  partitions,  though  they  extend 
more  or  less  inward  in  proportion  to  their  age,  do  not  unite 
with  the  digestive  sac,  but  leave  a  free  space  in  the  centre  be 
tween  their  inner  edge  and  the  outer  wall  of  the  digestive  sac. 
The  genital  organs  are  placed  on  the  inner  edgCvS  of  the  partitions, 
thus  hanging  as  it  were  at  the  door  of  the  chambers,  so  that 
when  hatched,  the  eggs  naturally  drop  into  the  main  cavity  of 
the  body,  whence  they  pass  into  the  second  smaller  sac  through 
an  opening  in  its  bottom  or  digestive  cavity,  and  thence  out 
through  the  mouth  into  the  water.  In  the  lower  Polyps,  as  in 
our  common  Actinia  for  instance,  these  organs  occur  on  all  the 
radiating  partitions,  while  among  the  higher  ones,  the  Halcy- 
onoids  for  example,  they  are  found  only  on  a  limited  number. 
This  limitation  in  the  repetition  of  identical  parts  is  always  found 
to  be  connected  with  structural  superiority. 

The  upper  margin  of  the  body  is  fringed  by  hollow  tentacles, 
each  of  which  opens  into  one  of  the  chambers.  All  parts  of  the 
animal  thus  communicate  with  each  other,  whatever  is  intro 
duced  at  the  mouth  circulating  through  the  whole  structure, 


Fig.  1.    Transverse  section  of  an  Actinia.     (Agassiz.} 


6  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

passing  first  into  the  digestive  cavity,  thence  through  the  opening 
in  the  bottom  into  the  main  chambered  cavity,  where  it  enters 
freely  into  all  the  chambers,  and  from  the  chambers  into  the  ten 
tacles.  The  rejected  portions  of  the  food,  after ,  the  process  of 
digestion  is  completed,  return  by  the  same  road' arid"  are  thrown 
out  at  the  mouth. 

These  general  features  exist  in  all  Polyps,  and  Whether  they 
lead  an  independent  life  as  the  Actinia,  or  are;  combined  in  com 
munities,  like  most  of  the  corals  and  the  Halcyonpids, ;  'whether  the 
tentacles  are  many  or  few ;  whether  the  partitions  extend  to  a 
greater  or  less  height  in  the  body ;  whether  .they  contain  limestone 
deposit,  as  in  the  corals,  or  remain  soft  thrpughout  life  as  the  sea- 
anemone, —  the  above  description  applies  •  to  them  all,  while  the 
minor  differences,  either  in  the  tentacles  or -in  the;  form,  size,  color, 
and  texture  of  the  body,  are  simply  modifications  of  this  structure, 
introducing  an  infinite  variety  into  the  class,  and  .breaking  it  up 
into  the  lesser  groups  designated  as  orders,' families,  genera,  and 
species.  Let  us  now  look  at  some  of  the  divisions  thus  estab 
lished.  .'  --  .  ,<;'>  t-v 

The  class  of  Polyps  is  divided  into  three  orders,  —  the  Halcy- 
onoids,  the  Madreporians,  and  the  Actinoids.  Of  the  lowest 
among  these  orders,  the  Actinoid  Polyps,  our  -Actinia  or  sea-ane 
mone  is  a  good  example.  They  remain  soft  .-through  life,  having 
a  great  number  of  partitions  and  consequentty.a  great  number  of 
tentacles,  since  there  is  a  tentacle  corresponding  to  every  cham 
ber.  Indeed,  in  this  order  the  multiplication  of  tentacles  and 
partitions  is  indefinite,  increasing  during  the  whole  life  of  the 
animal  with  its  growth ;  while  we  shall  see;  that  in  some  of  the 
higher  orders  the  constancy  and  limitation  in  the  number  of  these 
parts  is  an  indication  of  superiority,  being  accompanied  by  a 
more  marked  individualization  of  the  different  functions. 

Next  come  the  Madreporians,  of  which  our  Astrangia,  to  be 
described  hereafter,  may  be  cited  as  an  example.  In  this  group, 
although  the  number  of  tentacles  still  continues  to  be  large,  they 
are  nevertheless  more  limited  than  in  the  Actinoids ;  but  their 
characteristic  feature  is  the  deposition  of  limestone  walls  in  the 
centre  of  the  chambers  formed  by  the  soft  partitions,  so  that  all 
the  soft  partitions  alternate  with  hard  ones.  The  tentacles,  al- 


ACTINOIDS.  7 

ways  corresponding  to  the  cavity  of  the  chambers,  may  be  there 
fore  said  to  ride  this  second  set  of  partitions  arising  just  in  the 
centre  of  the  chambers. 

The  third  and  highest  order  of  Polyps  is  that  of  the  Halcyo- 
noids.  Here  the  partitions  are  reduced  to  eight ;  the  tentacles, 
according  to  the  invariable  rule,  agree  in  number  with  the  cham 
bers,  but  have  a  far  more  highly  complicated  structure  than  in 
the  lower  Polyps.  Some  of  these  Halcyonoids  deposit  limestone 
particles  in  their  frame.  But  the  tendency  to  solidify  is  not  lim 
ited  to  definite  points,  as  in  the  Madreporians.  It  may  take  place 
anywhere,  the  rigidity  of  the  whole  structure  increasing  of  course 
in  proportion  to  the  accumulation  of  limestone.  There  are  many 
kinds,  in  which  the  axis  always  remains  soft  or  cartilaginous, 
while  others,  as  the  so-called  sea-fans  for  instance,  well  known 
among  the  corals  for  their  beauty  of  form  and  color,  are  stiff 
and  hard  throughout.  Whatever  their  character  in  this  respect, 
however,  they  are  always  compound,  living  in  communities,  and 
never  found  as  separate  individuals  after  their  early  stages  of 
growth.  Some  of  those  with  soft  axis  lead  a  wandering  life, 
enjoying  as  much  freedom  of  movement  as  if  they  had  an  indi 
vidual  existence,  shooting  through  the  water  like  the  Pennatulae, 
well  known  on  the  California  coast,  or  working  their  way  through 
the  sand  like  the  Renilla,  common  on  the  sandy  shores  of  our 
Southern  States. 


ACTINOIDS. 

Actinia,  or  Sea-Anemone.     (Metridium  marginatum  EDW.) 

NOTHING  can  be  more  unprepossessing  than  a  sea-anemone  when 
contracted.  A  mere  lump  of  brown  or  whitish  jelly,  it  lies  like 
a  lifeless  thing  on  the  rock  to  which  it  clings,  and  it  is  difficult  to 
believe  that  it  has  an  elaborate  and  exceedingly  delicate  inter 
nal  organization,  or  will  ever  expand  into  such  grace  and  beauty 
as  really  to  deserve  the  name  of  the  flower  after  which  it  has  been 
called.  Figs.  2,  3,  4,  and  5,  show  this  animal  in  its  various  stages 


8  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

of  expansion  and  contraction.  Fig.  2  represents  it  with  all  its 
external  appendages  folded  in,  and  the  whole  body  flattened  ;  in 
Fig.  3,  the  tentacles  begin  to  steal  out,  arid  the  body  rises  slightly  ; 
in  Fig.  4,  the  body  has  nearly  gained  its  full  height,  and  the  ten- 
Fig.  2.  Fig.  3.  Fig.  4. 


tacles,  though  by  no  means  fully  spread,  yet  form  a  delicate 
wreath  around  the  mouth ;  while  in  Fig.  5,  drawn  in  life  size,  the 

Fig.  5. 


Figs.  2,  3,  4      Actinia  in  different  degrees  of  expansion.     (Ayassiz.) 

Fig.  5.     The  same  Actinia  (Metridium  marginatum)  fully  expanded  ;  natural  size. 


METRIDIUM.  y 

whole  summit  of  the  body  seems  crowned  with  soft,  plumy  fringes. . 
We  would  say  for  the  benefit  of  collectors  that  these  animals  are 
by  no  means  difficult  to  find,  and  thrive  well  in  confinement, 
though  it  will  not  do  to  keep  them  in  a  small  aquarium  with 
other  specimens,  because  they  soon  render  the  water  foul  and  . 
unfit  for  their  companions.     They  should  therefore  be  kept   in 
a  separate  glass  jar  or  bowl,  and  under  such  circumstances  will 
live  for  a  long  time  with  comparatively  little  care. 

They  may  be  found  in  any  small  pools  about  the  rocks  which 
are  flooded  by  the  tide  at  high  water.  Their  favorite  haunts, 
however,  where  they  occur  in  greatest  quantity  are  more  difficult 
to  reach ;  but  the  curious  in  such  matters  will  be  well  rewarded, 
even  at  the  risk  of  wet  feet  and  a  slippery  scramble  over  rocks 
covered  with  damp  sea-weed,  by  a  glimpse  into  their  more  crowded 
abodes.  Such  a  grotto  is  to  be  found  on  the  rocks  of  East  Point 
at  Nahant.  It  can  only  be  reached  at  low  tide,  and  then  one  is 
obliged  to  creep  on  hands  and  knees  to  its  entrance,  in  order  to 
see  through  its  entire  length  ;  but  its  whole  interior  is  studded 
with  these  animals,  and  as  they  are  of  various  hues,  pink,  brown, 
orange,  purple,  or  pure  white,  the  effect  is  like  that  of  brightly 
colored  mosaics  set  in  the  roof  and  walls.  When  the  sun  strikes 
through  from  the  opposite  extremity  of  this  grotto,  which  is  open 
at  both  ends,  lighting  up  its  living  mosaic  work,  and  showing  the 
play  of  the  soft  fringes  wherever  the  animals  are  open,  it  would 
be  difficult  to  find  any  artificial  grotto  to  compare  with  it  in 
beauty.  There  is  another  of  the  same  kind  on  Saunders's  Ledge, 
formed  by  a  large  boulder  resting  on  two  rocky  ledges,  leaving  a 
little  cave  beneath,  lined  in  the  same  way  with  variously  colored 
sea-anemones,  so  closely  studded  over  its  walls  that  the  surface 
of  the  rock  is  completely  hidden.  They  are,  however,  to  be  found 
in  larger  or  smaller  clusters,  or  scattered  singly  in  any  rocky  fis 
sures,  overhung  by  sea-weed,  and  accessible  to  the  tide  at  high 
water. 

The  description  of  Polyp  structure  given  above  includes  all  the 
general  features  of  the  sea-anemone  ;  but  for  the  better  explana 
tion  of  the  figures,  it  may  not  be  amiss  to  recapitulate  them  here 
in  their  special  application.  The  body  of  the  sea-anemone  may  be 
described  as  a  circular,  gelatinous  bag,  the  bottom  of  which  is  flat 

2 


10  MARINE   ANIMALS    OF   MASSACHUSETTS   BAY. 

and  slightly  spreading  around  the  margin.    (Fig.  2.)     The  upper 
edge  OL  this  bag  turns  in  so  as  to  form  a  sac  within  a  sac.    (Fig. 
Fig.  e.  6.)    This  inner  sac,  s,  is  the  stomach  or 

digestive  cavity,  forming  a  simple  open 
space  in  the  centre  of  the  body,  with  an 
aperture  in  the  bottom,  5,  through  which 
the  food  passes  into  the  larger  sac,  in 
which  it  is  enclosed.  But  this  outer 
and  larger  sac  or  main  cavity  of  the 
body  is  not,  like  the  inner  one,  a  simple  open  space.  It  is,  on  the 
contrary,  divided  by  vertical  partitions  into  a  number  of  distinct 
chambers,  converging  from  the  periphery  to  the  centre.  These 
partitions  do  not  all  advance  so  far  as  actually  to  join  the  wall  of 
the  digestive  cavity  hanging  in  the  centre  of  the  body,  but  most 
of  them  stop  a  little  short  of  it,  leaving  thus  a  small,  open  space 
between  the  chambers  and  the  inner  sac.  (Fig.  1.)  The  eggs 
hang  on  the  inner  edge  of  the  partitions  ;  when  mature  they 
drop  into  the  main  cavity,  enter  the  inner  digestive  cavity  through 
its  lower  opening,  and  are  passed  out  through  the  mouth. 

The  embryo  bears  no  resemblance  to  the  mature  animal.  It  is 
a  little  planula,  semi-transparent,  oblong,  entirely  covered  with 
vibratile  cilia,  by  means  of  which  it  swims  freely  about  in  the 
water  till  it  establishes  itself  on  some  rocky  surface,  the  end 
by  which  it  becomes  attached  spreading  slightly  and  fitting 
itself  to  the  inequalities  of  the  rock  so  as  to  form  a  secure  basis. 
The  upper  end  then  becomes  depressed  toward  the  centre,  that 
depression  deepening  more  and  more  till  it  forms  the  inner  sac, 
or  in  other  words  the  digestive  cavity  described  above.  The  open 
mouth  of  this  inner  sac,  which  may,  however,  be  closed  at  will, 
since  the  whole  substance  of  the  body  is  exceedingly  contractile, 
is  the  oral  opening  or  so-called  mouth  of  the  animal.  We  have 
seen  how  the  main  cavity  becomes  divided  by  radiating  partitions 
into  numerous  chambers  ;  but  while  these  internal  changes  are 
going  on,  corresponding  external  appendages  are  forming  in  the 
shape  of  the  tentacles,  which  add  so  much  to  the  beauty  of  the 
animal,  and  play  so  important  a  part  in  its  history.  The  ten- 
Fig.  6.  Vertical  section  of  an  Actinia,  showing  a  primary  (gr)  and  a  secondary  partition  g'  ;  o  mouth, 
t  tentacles,  s  stomach,  //  reproductive  organs,  b  main  cavity,  c  openings  in  partitions,  a  lower  floor,  or 
foot. 


METRIDIUM. 


11 


Fig.  7. 


tacles,  at  first  only  few  in  number,  are  in  fact  so  many  extensions 

of  the   inner  chambers,  gradually  narrowing  upward  till  they 

form  these  delicate  hollow  feelers  which  make  a  soft  downy  fringe 

all  around  the  mouth.   (Fig.  7.)    They  do  not  start  abruptly  from 

the  summit,  but  the  upper  margin 

of   the    body   itself    thins    out   to 

form  more  or  less  extensive  lobes, 

through  which  the  partitions  and 

chambers    continue    their    course, 

and  along  the  edge  of  which  the 

tentacles  arise. 

The  eggs  are  not  always  laid  in 
the  condition  of  the  simple  planula 
described  above.  They  may,  on  the  *'"•;•  ly'- 

contrary,  be  dropped  from  the  par-  Wv' 

ent  in  different  stages  of  develop-  ^ 

ment,  sometimes  even  after  the  tentacles  have  begun  to  form,  as 
in  Figs.  8,  9.     Neither  is  it  by  means  of  eggs  alone  that  these 


W 


Fig. 


Fig.  9. 


animals  reproduce  themselves  ;  they  may  also  multiply  by  a  pro 
cess  of  self-division.  The  disk  of  an  Actinia  may  contract  along 
its  centre  till  the  circular  outline  is  changed  to  that  of  a  figure  8, 
this  constriction  deepening  gradually  till  the  two  halves  of  the  8 
separate,  and  we  have  an  Actinia  with  two  mouths,  each  sur 
rounded  by  an  independent  set  of  tentacles.  Presently  this  sepa 
ration  descends  vertically  till  the  body  is  finally  divided  from 

Fig.  7.    View  from  above  of  an  Actinia  with  all  its  tentacles  expanded  ;  o  mouth,  b  crescent-shaped 
folds  at  extremity  of  mouth,  a  a  folds  round  mouth,  1 1 1  tentacles. 
Figs.  8,  9.    Young  Actiuiie  in  different  stages  of  growth. 


12  MARINE   ANIMALS    OF    MASSACHUSETTS    BAY. 

summit  to  base,  and  we  have  two  Actiniae  where  there  was  origi 
nally  but  one.  Another  and  a  far  more  common  mode  of  re 
production  among  these  animals  is  that  of  budding  like  corals. 
A  slight  swelling  arises  011  the  side  of  the  body  or  at  its  base ; 
it  enlarges  gradually,  a  digestive  cavity  is  formed  within  it,  tenta 
cles  arise  around  its  summit,  and  it  finally  drops  off  from  the 
parent  and  leads  an  independent  existence.  As  a  number  of 
these  buds  are  frequently  formed  at  once,  such  an  Actinia,  sur 
rounded  by  its  little  family,  still  attached  to  the  parent,  may  ap 
pear  for  a  time  like  a  compound  stock,  though  their  normal  mode 
of  existence  is  individual  and  distinct. 

The  Actinia  is  exceedingly  sensitive,  contracting  the  body  and 
drawing  in  the  tentacles  almost  instantaneously  at  the  slightest 
touch.  These  sudden  movements  are  produced  by  two  powerful 
sets  of  muscles,  running  at  right  angles  with  each  other  through 
the  thickness  of  the  body  wall ;  the  one  straight  and  vertical,  ex 
tending  from  the  base  of  the  wall  to  its  summit ;  the  other  cir 
cular  and  horizontal,  stretching  concentrically  around  it.  By 
the  contraction  of  the  former,  the  body  is  of  course  shortened  ;  by 
the  contraction  of  the  latter,  the  body  is,  on  the  contrary,  length 
ened  in  proportion  to  the  compression  of  its  circumference.  Both 
sets  can  easily  be  traced  by  the  vertical  and  horizontal  lines  cross 
ing  each  other  011  the  external  wall  of  the  body,  as  in  Fig.  5. 
Each  tentacle  is  in  like  manner  furnished  with  a  double  set  of 
muscles,  having  an  action  similar  to  that  described  above.  In 
consequence  of  these  violent  muscular  contractions,  the  water  im 
bibed  by  the  animal,  and  by  which  all  its  parts  are  distended  to 
the  utmost,  is  forced,  not  only  out  of  the  mouth,  but  also  through 
small  openings  in  the  body  wall  scarcely  perceptible  under  ordi 
nary  circumstances,  but  at  such  times  emitting  little  fountains  in 
every  direction. 

Notwithstanding  its  extraordinary  sensitiveness,  the  organs  of 
the  senses  in  the  Actinia  are  very  inferior,  consisting  only  of  a 
few  pigment  cells  accumulated  at  the  base  of  the  tentacles.  The 
two  sets  of  muscles  meet  at  the  base  of  the  body,  forming  a  disk, 
or  kind  of  foot,  by  which  the  animal  can  fix  itself  so  firmly  to 
the  ground,  that  it  is  very  difficult  to  remove  it  without  in 
jury.  It  is  nevertheless  capable  of  a  very  limited  degree  of 


RHOD  ACTINIA.  13 

motion,  by  means  of  the  expansion  and  contraction  of  this  foot- 
like  disk. 

The  Actinias  are  extremely  voracious  ;  they  feed  on  mussels 
and  cockles,  sucking  the  animals  out  of  their  shells.  When  in 
confinement  they  may  be  fed  on  raw  meat,  and  seem  to  relish  it ; 
but  if  compelled  to  do  so,  they  will  live  on  more  meagre  fare,  and 
will  even  thrive  for  a  long  time  on  such  food  as  they  may  pick 
up  in  the  water  where  they  are  kept. 

Rhodactinia.     (Rhodactinia  Davisii  AG.) 

Very  different  from  this  is  the  bright  red  Rhodactinia  (Fig. 
10),  quite  common  in  the  deeper  waters  of  our  bay,  while  far 
ther  nor tli,  in  Maine,  it  occurs  at  low-water  mark.  Occasion 
ally  it  may  be  found  thrown  up  on  our  sandy  beaches  after  a 
storm,  and  then,  if  it  has  not  been  too  long  out  of  its  native 
element,  or  too  severely  buffeted  by  the  waves,  it  will  revive  on 
being  thrown  into  a  bucket 

f.       ?       ,  Fig.  10. 

ot  iresn  sea-water,  expand 
to  its  full  size,  and  show  all 
the  beauty  of  its  natural  col 
oring.  It  is  crowned  with  a 
wreath  of  thick,  short  tenta 
cles  (Fig.  10),  and  though  so 
vivid  and  bright  in  color,  it 
is  not  so  pretty  as  the  more 
common  Actinia  marginata, 
with  its  soft  waving  wreath  of 
plume-like  feelers,  in  compar 
ison  to  which  the  tentacles  of  the  Rhodactinia  are  clumsy  and 
slow  in  their  movements. 

All  Actiniae  are  not  attached  to  the  soil  like  those  described 
above,  nor  do  they  all  terminate  in  a  muscular  foot,  some  being 
pointed  or  rounded  at  their  extremity.  Many  are  nomadic,  wan 
dering  about  at  will  during  their  whole  lifetime,  others  live 
buried  in  the  sand  or  mud,  only  extending  their  tentacles  beyond 
the  limits  of  the  hole  where  they  make  their  home  ;  while  others 
again  lead  a  parasitic  life,  fastening  themselves  upon  our  larger 

Fig.  10.     Rhodactinia  Davisii  Ag. ;  natural  size. 


14 


MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 


jelly-fish,  the  Cyaneae,  though  one  is  at  a  loss  to  imagine  what 
sustenance  they  can  derive  from  animals  having  so  little  solidity, 
and  consisting  so  largely  of  water. 

ArachnactlS.     (Arachnactis  brachiolata  A.  AG.) 


Fig.  11. 


Fig.  12. 


Among  the  nomadic  Polyps  is  a  small 
floating  Actinia,  called  Arachnactis, 
(Fig.  11,)  from  its  resemblance  to  a 
spider.  They  are  found  in  great  plenty 
floating  about  during  the  night,  feeling 
their  way  in  every  direction  by  means 
of  their  tentacles,  which  are  large 
in  proportion  to  the  size  of  the  animal, 
few  in  number,  and  turned  downward 
when  in  their  natural  attitude.  The 
partitions  and  the  digestive  cavity  en 
closed  between  them  are  short,  as  will 
be  seen  in  Fig.  11,  when  compared  to 
the  general  cavity  of  the  body  floating 
balloon-like  above  them.  Around  the 
mouth  is  a  second  row  of  shorter  ten 
tacles,  better  seen  in  a  younger  speci 
men  (Fig.  12).  This  Actinia  differs 
from  those  described  above,  in  having 
two  of  the  sides  flattened,  instead  of 
being  perfectly  circular.  Looked  at 
from  above  (as  in  Fig.  13)  this  differ 
ence  in  the  diameters  is  very  percepti 
ble  ;  there  is  an  evident  tendency  to 
wards  establishing  a  longitudinal  axis. 
In  the  sea-anemone,  this  disposition  is 
only  hinted  at  in  the  slightly  pointed 
folds  or  projections  on  opposite  sides  of 
the  circle  formed  by  the  mouth,  which 
in  the  Arachnactis  are  so  elongated  as 
to  produce  a  somewhat  narrow  slit  (see 


Fig.  11. 

Fig.  13. 


Arachnactis  brachiolata  A.  Ag.,  greatly  magnified. 
Young  Arachnactis  seen  so  as  to  show  the  mouth. 


Fig.  12.    Young  Arachnactis. 


BICIDIUM.  15 

Fig.  13),  instead  of  a  circular  opening.  The  mouth  is  also  a 
little  out  of  centre,  rather  nearer  one  end  of  the  disk  than  the 
other.  These  facts  are  interesting,  as  showing  that  the  ten 
dency  towards  establishing  a  balance  of  parts,  as  between  an  an 
terior  and  posterior  extremity,  a  right  and  left  side,  is  not  forgot 
ten  in  these  lower  animals,  though  their  organization  as  a  whole 
is  based  upon  an -equality  of  parts,  admitting  neither  of  pos 
terior  and  anterior  extremities,  nor  of  right  and  left,  nor  of 
above  and  below,  in  a  structural  sense.  This  animal  also  pre 
sents  a  seeming  anomaly  in  the  mode  of  formation  of  the 
young  tentacles,  which  always  make  their  appearance  at  the 
posterior  extremity  of  the  longitudinal  axis,  the  new  ones  being 
placed  behind  the  older  ones,  instead  of  alternating  with  them  as 
in  other  Actiniae. 


Bicidium.     (Biddium  parasiticum  AG.) 

The  Bicidium  (Fig.  14),  our  parasitic  Actinia,  is  to  be  sought 
for  in  the  mouth-folds  of  the  Cyanea,  our  common  large  red 
Jelly-fish.  In  any  moderate-sized  specimen  of  the  latter  from 
twelve  to  eighteen  inches  in  diameter,  we  shall  be  sure  to  find 
one  or  more  of  these  parasites,  hidden  away  among  the  numerous 
folds  of  the  mouth.  The  body  is  long  and  tapering,  having  an  ap 
erture  in  the  extremity,  the  whole  animal  being  Fig.  14. 
like  an  elongated  cone,  strongly  ribbed  from 
apex  to  base.  At  the  base,  viz.  at  the  mouth 
end,  are  a  few  short,  stout  tentacles.  This  Ac 
tinia  is  covered  with  innumerable  little  trans 
verse  wrinkles  (see  Fig.  14) ,  by  means  of  which 
it  fastens  itself  securely  among  the  fluted  mem 
branes  around  the  mouth  of  the  Jelly-fish.  It 
will  live  a  considerable  time  in  confinement,  at 
taching  itself,  for  its  whole  length,  to  the  vessel 
in  which  it  is  kept,  and  clinging  quite  firmly  if 
any  attempt  is  made  to  remove  it.  The  general 
color  of  the  body  is  violet  or  a  brownish  red, 
though  the  wrinkles  give  it  a  somewhat  mottled  appearance. 

Fig.  14.      Bicidium  parasiticum;  natural  size. 


16 


MARINE    ANIMALS    OF   MASSACHUSETTS    BAY. 


Fig.  15 


Halcampa.      (Halcampa  albida  Ac.) 

Strange  to  say,  the  Actiniae,  which  live  in  the  mud,  are 
among  the  most  beautifully  colored  of  these  animals.  They 
frequently  prepare  their  home  with  some  care,  lining  their  hole 
by  means  of  the  same  secretions  which  give  their  slimy  surface 
to  our  common  Actiniae,  and  thus  forming  a  sort  of  tube,  into 
which  they  retire  when  alarmed.  But  if  undis 
turbed,  they  may  be  seen  at  the  open  door  of 
their  house  with  their  many-colored  disk  and 
mottled  tentacles  extending  beyond  the  aperture, 
and  their  mouth  wide  open,  waiting  for  what  the 
tide  may  bring  them.  By  the  play  of  their  ten 
tacles,  they  can  always  produce  a  current  of 
water  about  the  mouth,  by  means  of  which  food 
passes  into  the  stomach.  We  have  said,  that 
these  animals  are  very  brightly  colored,  but  the 
little  Halcampa  (Fig.  15),  belonging  to  our  coast, 
is  not  one  of  the  brilliant  ones.  It  is,  on  the 
contrary,  a  small,  insignificant  Actinia,  resem 
bling  a  worm,  as  it  burrows  its  way  through  the 
sand.  It  is  of  a  pale  yellowish  color,  with  whitish  warts  on  the 
surface. 


MADREPORIANS. 

Astrangid.      (Astrangia  Dance  AG.) 

IN  Figure  16,  we  have  the  only  species  of  coral  growing 
so  far  north  as  our  latitude.  Indeed,  it  hardly  belongs  in 
this  volume,  since  we  have  limited  ourselves  to  the  Radiates  of 
Massachusetts  Bay,  —  its  northernmost  boundary  being  some 
what  to  the  south  of  Massachusetts  Bay,  about  the  shores  of 
Long  Island,  and  on  the  islands  of  Martha's  Vineyard  Sound. 
But  we  introduce  it  here,  though  it  is  not  included  under  our 

Fig.  15.    Halcampa  albida-,  natural  size. 


MADREPORIANS.  17 

title,  because  any  account  of  the  Radiates,  from  which  so  impor 
tant  a  group  as  that  of  the  corals  was  excluded,  would  be  very 
incomplete. 

This    pretty   coral   of  Fig.  10. 

our  Northern  waters  is 
no  reef-builder,  and  does 
not  extend  farther  south 
than  the  shores  of  North 
Carolina.  It  usually  es 
tablishes  itself  upon  brok 
en  angular  bits  of  rock, 
lying  in  sheltered  creeks 
and  inlets,  where  the  vio 
lent  action  of  the  open  sea  is  not  felt.  The  presence  of  one  of 
these  little  communities  on  a  rock  may  first  be  detected  by  what 
seems  like  a  delicate  white  film  over  the  surfkce.  This  film  is, 
however,  broken  up  by  a  number  of  hard  calcareous  deposits  in 
very  regular  form  (Fig.  20),  circular  in  outline,  but  divided  by 
numerous  partitions  running  from  the  outer  wall  to  the  centre  of 
every  such  circle,  where  they  unite  at  a  little  white  spot  formed  by 
the  mouth  or  oral  opening.  These  circles  represent,  and  indeed 
are  themselves  the  distinct  individuals  (Fig.  17)  composing  the 
community,  and  they  look  Fig.  17. 

not  unlike  the  star-shaped 
pits  on  a  coral  head,  formed 
by  Astraeans.  Unlike  the 
massive  compact  kinds  of 
coral,  however,  the  indi 
viduals  multiply  by  bud 
ding  from  the  base  chiefly, 
never  rising  one  above  the 
other,  but  spreading  over 
the  surface  on  which  they 
have  established  them 
selves,  a  few  additional  individuals  arising  between  the  older 
ones.  In  consequence  of  this  mode  of  growth,  such  a  commu- 

Fig.  16.     Astranpria  colony 5  natural  size. 

Fig.  17.    Magnified  individuals  of  an  Astrangia  community  in  different  stages  of  expansion. 
3 


18  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

nity,  when  it  has  attained  any  size,  forms  a  little  white  mound  on 
the  rock,  higher  in  the  centre,  where  the  older  members  have 
attained  their  whole  height  and  solidity,  and  thinning  out  toward 
the  margin,  where  the  younger  ones  may  be  just  beginning  life, 
and  hardly  rise  above  the  surface  of  the  rock.  These  communi 
ties  .rarely  grow  to  be  more  than  two  or  three  inches  in  diameter, 
and  about  quarter  of  an  inch  in  height  at  the  centre  where  the 
individuals  have  reached  their  maximum  size.  When  the  ani 
mals  are  fully  expanded  (Fig.  18),  with  all  their  tentacles  spread, 
i<r  18>  the  surface  of  every  such  mound 

becomes  covered  with  downy 
white  fringes,  and  what  seemed 
before  a  hard,  calcareous  mass 
upon  the  rock,  changes  to  a  soft 
fleecy  tuft,  waving  gently  to  and 
fro  in  the  water.  The  tentacles 
are  thickly  covered  with  small  wart-like  appendages,  which,  on 
examination,  prove  to  be  clusters  of  lasso-cells,  the  terminal 
cluster  of  the  tentacle  being  quite  prominent.  These  lasso-cells 
are  very  formidable  weapons,  judging  both  from  their  appearance 
when  magnified  (Fig.  19),  and  from  the  terrible  effect  of  their 
bristling  lash  upon  any  small  crustacean,  or  worm,  that 
may  be  so  unfortunate  as  to  come  within  its  reach. 

The  description  of  the  internal  arrangement  of  parts 
in  the  Actinia  applies  in  every  particular  to  these  corals, 
with  the  exception  of  the  hard  deposit  in  the  lower  part 
of  the  body.  As  in  all  the  Polyps,  radiating  partitions 
divide  the  main  cavity  of  the  body  into  distinct  separate 
chambers,  and  the  tentacles  increasing  by  multiples  of 
six,  numbering  six  in,  the  first  set,  six  in  the  second,  and 
twelve  in  the  third,  are  hollow,  and  open  into  the  cham 
bers.  But  the  feature  which  distinguishes  them  from 
the  soft  Actinia?,  and  unites  them  with  the  corals,  re 
quires  a  somewhat  more  accurate  description.  In  each 
individual,  a  hard  deposit  is  formed  (Fig.  20),  beginning 
at  the  base  of  every  chamber,  and  rising  from  its  floor  to  about 

Fig.  18.    Single  individual  of  Astrangia,  fully  expanded. 
Fig.  19.    Magnified  lasso-cell  of  Astrangia. 


HALCYOXOIDS. 


19 


one  fifth  the  height  of  the  animal  at  its  greatest  extension.  This 
lime  deposit  does  not,  however,  fill  Fig  20 

the  chamber  for  its  whole  width,  but 
rises  as  a  thin  wall  in  its  centre.  (See 
Figs.  16,  IT.)  Thus  between  all  the 
soft  partitions,  in  the  middle  of  the 
chambers  which  separate  them,  low 
lime-stone  walls  are  gradually  built 
up,  uniting  in  a  solid  column  in  the 
centre.  These  walls  run  parallel 
with  the  soft  partitions,  although 
they  do  not  rise  to  the  same  height, 

and  they  form  the  radiating  lines  like  stiff  lamellae,  so  conspicu 
ous  when  all  the  soft  parts  of  the  body  are  drawn  in.  The  mouth 
of  the  Astrangia  is  oval,  and  the  partitions  spread  in  a  fan-shaped 
way,  being  somewhat  shorter  at  one  side  of  the  animal  than  on 
the  other.  The  partitions  extend  beyond  the  solid  wall  which 
unites  them  at  the  periphery,  in  consequence  of  which,  this  wall 
is  marked  by  faint  vertical  ribs. 


HALCYONOIDS.X 


Haley  'Onium.      (Halcyonium 


Libr&ry* 


WE  come  now  to  the  Halcyonoids,  represented  in  our  waters 
by  the  Halcyonium  (Fig.  22).  In  the  Halcyonoids,  the 
highest  group  of  Polyps,  the  tentacles  reach  their  greatest 
limitation,  which,  as  above  mentioned,  is  found  to  be  a  mark 
of  superiority,  and,  connected  with  other  struc-  Fig.  21. 

tural  features,  places  them  at  the  head  of  their 
class.  The  number  of  tentacles  throughout  this 
group  is  always  eight.  They  are  very  compli 
cated  (Fig.  21),  in  comparison  with  the  tenta 
cles  of  the  lower  orders,  being  deeply  lobed, 


Fig.  20.    Limestone  parts  of  an  individual  of  Astrangia;  magnified. 
Fig.  21.    Single  individual  of  Halcyonium  seen  from  above;  magnified. 


20  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

and  fringed  around  the  margin.     Our  Halcyonium  communities 
r.    22  (Fig.  22)  iisually  live  in  deep  water, 

attached  to  dead  shells,  though  they 
may  occasionally  be  found  growing  at 
low-water  mark,  but  this  is  very  rare. 
They  have  received  a  rather  lugubri 
ous  name  from  the  fishermen,  who  call 
them  "  dead-men's  fingers,"  and  in 
deed,  when  the  animals  are  contract 
ed,  such  a  community,  with  its  short 
branches  attached  to  the  main  stock, 
looks  not  unlike  the  stump  of  a  hand, 
with  short,  fat  fingers.  In  such  a  con 
dition  they  are  very  ugly,  the  whole 
mass  being  somewhat  gelatinous  in  tex 
ture,  and  a  dull,  yellowish  pink  in  color. 
But  when  the  animals,  which  are  capable  of  great  extension,  are 
fully  spread,  as  in  Fig.  22,  such  a  polyp-stock  has  a  mossy,  tufted 
look,  and  is  by  no  means  an  unsightly  object.  When  the  individ 
uals  are  entirely  expanded,  as  in  Fig.  23,  they  be 
come  quite  transparent,  and  their  internal  structure 
can  readily  be  seen  through  the  walls  of  the  body  ; 
we  can  then  easily  distinguish  the  digestive  cavity, 
supported  for  its  whole  length  by  the  eight  radiating 
partitions,  as  well  as  the  great  size  of  the  main  diges 
tive  cavity  surrounding  it.  Notwithstanding  the  re 
markable  power  of  contraction  and  dilatation  in 
the  animals  themselves,  the  tentacles  are  but  slight 
ly  contractile.  This  kind  of  community  increases 
altogether  by  budding,  the  individual  polyps  remaining  more  or 
less  united,  the  tissues  of  the  individuals  becoming  thicker  by 
the  deposition  of  lime  nodules,  and  thus  forming  a  massive 
semi-cartilaginous  pulp,  uniting  the  whole  community.  In  the 
neighborhood  of  Provincetown  they  are  very  plentiful,  and  are 
found  all  along  the  shores  of  our  Bay  in  deep  water. 

Fig.  22.    Ilalcyonium  community,  natural  size. 

Fig.  23.    Individual  of  Ilalcyonium  fully  expanded  j  magnified. 


GENERAL  SKETCH  OF  ACALEPHS.  21 


GENERAL  SKETCH  OF  ACALEPHS. 

IN  the  whole  history  of  metamorphosis,  that  wonderful  chapter 
in  the  life  of  animals,  there  is  nothing  more  strange  or  more  in 
teresting  than  the  transformations  of  the  Acalephs.  First,  as 
little  floating  planulae  or  transparent  spheres,  covered  with  fine 
vibratile  cilia,  by  means  of  which  they  move  with  great  rapidity, 
then  as  communities  fixed  to  the  ground  and  increasing  by  bud 
ding  like  the  corals,  or  multiplying  by  self-division,  and  later  as 
free-swimming  Jelly-fishes,  many  of  them  pass  through  phases 
which  have  long  baffled  the  investigations  of  naturalists,  and  have 
only  recently  been  understood  in  their  true  connection.  Great 
progress  has,  however,  been  made  during  this  century  in  our 
knowledge  of  this  class.  Thanks  to  the  investigations  of  Sars,  Du- 
jardin,  Steenstrup,  Van  Beneden,  and  many  others,  we  now  have 
the  key  to  their  true  relations,  and  transient  phases  of  growth, 
long  believed  to  be  the  adult  condition  of  distinct  animals,  are 
now  recognized  as  parts  in  a  cycle  of  development  belonging  to 
one  and  the  same  life.  As  the  class  now  stands,  it  includes  three 
orders,  highest  among  which  are  the  CTENOPHOILE,  so  called  on 
account  of  their  locomotive  organs,  consisting  of  minute  flappers 
arranged  in  vertical  comb-like  rows  ;  next  to  these  are  the  Dis 
COPHOR.E,  with  their  large  gelatinous  umbrella-like  disks,  com 
monly  called  Jelly-fishes,  Sun-fishes,  or  Sea-blubbers,  and  below 
these  come  the  HYDROIDS,  embracing  the  most  minute  and  most 
diversified  of  all  these  animals. 

These  orders  are  distinguished  not  only  by  their  striking  ex 
ternal  differences,  but  by  their  mode  of  development  also.  The 
Ctenophoras  grow  from  eggs  by  a  direct  continuous  process  of 
development,  without  undergoing  any  striking  metamorphosis  ; 
the  Discophorae,  with  some  few  exceptions,  in  which  they  develop 
like  the  Ctenophorae  from  eggs,  begin  life  as  a  Hydra-like  ani 
mal,  the  subsequent  self-division  of  which  gives  rise,  by  a  singular 
process,  presently  to  be  described,  to  a  number  of  distinct  Jelly- 
fishes  ;  the  Hydroids  include  all  those  Acalephs  which  either 
pass  the  earlier  stages  of  their  existence  as  little  shrub-like  com- 


22 


MARINE    ANIMALS    OF   MASSACHUSETTS    BAY. 


Fig.  24. 


munities,  or  remain  in  that  condition  through  life.  These  Hy 
droid  stocks,  as  they  are  sometimes  called,  give  rise  to  buds ; 
these  buds  are  transformed  into  Jelly-fishes,  which  in  some  in 
stances  break  off  when  mature  and  swim  away  as  free  animals, 
while  in  others  they  remain  permanent  members  of  the  Hydroid 
stock,  never  assuming  a  free  mode  of  life.  All  these  buds  when 
mature,  whether  free  or  fixed,  lay  eggs  in  their  turn,  from  which 
a  fresh  stock  arises  to  renew  this  singular  cycle  of  growth,  known 
among  naturalists  as  "  alternate  generations." 

The  Hydroids  are  not  all  attached  to  the  ground,  —  some 
like  the  Physalia  (Portuguese  man-of-war),  or  the  Nanomia,  that 
pretty  floating  Hydroid  of  our  own  waters,  move  about  with  as 
much  freedom  as  if  they  enjoyed  an  individual  independent  ex 
istence.  As  all  these  orders  have  their  representatives  on  our 
coast,  to  be  described  hereafter  in  detail,  we  need  only  allude 
here  to  their  characteristic  features.  But  we  must  not  leave  un 
noticed  one  very  remarkable  Hydroid  Acaleph  (Fig.  24),  not 
found  in  our  waters,  and  resembling  the 
Polyps  so  much,  that  it  has  long  been  asso 
ciated  with  them.  The  Millepore  is  a  coral, 
and  was  therefore  the  more  easily  confounded 
with  the  Polyps,  so  large  a  proportion  of 
which  build  coral  stocks ;  but  a  more  mi 
nute  investigation  of  its  structure  (Figs.  25, 
26)  has  recently  shown  that  it  belongs  with 
the  Acalephs.*  This  discovery  is  the  more 
important,  not  only  as  explaining  the  true  po 
sition  of  this  animal  in  the  Animal  Kingdom, 
but  as  proving  also  the  presence  of  Acalephs 
in  the  earliest  periods  of  creation,  since  it  re 
fers  a  large  number  of  fossil  corals,  whose 
affinities  with  the  millepores  are  well  under 
stood,  to  that  class,  instead  of  to  the  class  of 
Polyps  with  which  they  had  hitherto  been  associated.  But  for 
this  we  should  have  no  positive  evidence  of  the  existence  of 

Fig.  24.    Branch  of  Millepora  alcicornis;  natural  size.     (Agassiz.") 

Fig.  25.     Animals  of  M.  alcicornis  expanded;  magnified,    aaa  small  Hydroid,  b  larger  Hydroid, 
I  tentacles,  m  mouth.    (Agassiz.) 

*  See  "  Methods  of  Study,"  by  Prof.  Agassiz. 


Fig.  25. 


GENERAL    SKETCH    OF    ACALEPHS.  23 

Acalephs    in   early   geological   periods,  the    gelatinous   texture 

of  the  ordinary  Jelly-fishes  making  their  preserva-        Kg.  26. 

tion  almost  impossible.     It  is  not  strange  that  the 

true   nature  of  this  animal  should  have  remained 

so   long  unexplained  ;   for   it   is   only   by  the    soft 

parts  of  the  body,  not  of  course  preserved  in  the 

fossil  condition,  that  their  relations  to  the  Acalephs 

may  be  detected  ;  and  they  are  so  shy  of  approach, 

drawing  their  tentacles  and  the  upper  part  of  the 

body   into   their   limestone   frame   if  disturbed,  that  it  is   not 

easy  to  examine  the  living  animal. 

The  Millepore  is  very  abundant  on  the  Florida  reefs.  From  the 
solid  base  of  the  coral  stock  arise  broad  ridges,  branching  more  or 
less  along  the  edges,  the  whole  surface  being  covered  by  innu 
merable  pores,  from  which  the  diminutive  animals  project  when 
expanded.  (Fig.  25.)  The  whole  mass  of  the  coral  is  porous, 
and  the  cavities  occupied  by  the  Hydras  are  sunk  perpendicularly 
to  the  surface  within  the  stock.  Seen  in  a  transverse  cut  these 
tubular  cavities  are  divided  at  intervals  by  horizontal  partitions 
(Fig.  26),  extending  straight  across  the  cavity  from  wall  to  wall, 
and  closing  it  up  entirely,  the  animal  occupying  only  the  outer 
most  open  space,  and  building  a  new  partition  behind  it  as  it 
rises  in  the  process  of  growth.  This  structure  is  totally  different 
from  that  of  the  Madrepores,  Astrasans,  Porites,  and  indeed,  from 
all  the  polyp  corals  which,  like  all  Polyps,  have  the  vertical  par 
titions  running  through  the  whole  length  of  the  body,  and  more 
or  less  open  from  top  to  bottom. 

The  life  of  the  Jelly-fishes,  with  the  exception  of  the  Mille- 
pores  and  the  like,  is  short  in  comparison  to  that  of  other  Radi 
ates.  While  Polyps  live  for  many  years,  and  Star-fishes  and 
Sea-urchins  require  ten  or  fifteen  years  to  attain  their  full  size, 
the  short  existence  of  the  Acaleph,  with  all  its  changes,  is  accom 
plished  in  one  year.  The  breeding  season  being  in  the  autumn, 
the  egg  grows  into  a  Hydroid  during  the  winter  ;  in  the  spring  the 
Jelly-fish  is  freed  from  the  Hydroid  stock,  or  developed  upon  it  as 
the  case  may  be ;  it  attains  its  full  size  in  the  fall,  lays  its  eggs 

Fiji.  26.    Transverse  section  of  a  branch,  showing  pits,  a  a  a  a,  of  the  large  Ilydroids  with  the  hori 
zontal  floors, 


24  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

and  dies,  and  the  cycle  is  complete.  The  autumn  storms  make 
fearful  havoc  among  them,  swarms  of  them  being  killed  by  the  fall 
rains,  after  which  they  may  be  found  thrown  up  on  the  beaches 
in  great  numbers.  When  we  consider  the  size  of  these  Jelly- 
fishes,  their  rapidity  of  growth  seems  very  remarkable.  Our 
common  Aurelia  measures  some  twelve  to  eighteen  inches  in 
diameter  when  full  grown,  and  yet  in  the  winter  it  is  a  Hydra  so 
small  as  almost  to  escape  notice.  Still  more  striking  is  the  rapid 
increase  of  our  Cyanea,  that  giant  among  Jelly-fishes,  which, 
were  it  not  for  the  soft,  gelatinous  consistency  of  its  body,  would 
be  one  of  the  most  formidable  among  our  marine  animals. 

Before  entering  upon  the  descriptions  of  the  special  kinds  of 
Jelly-fishes,  we  would  remind  our  readers  that  the  radiate  plan  of 
structure  is  reproduced  in  this  class  of  animals  as  distinctly  as  in 
the  Polyps,  though  under  a  different  aspect.  Here  also  we  find 
that  there  is  a  central  digestive  cavity  from  which  all  the  radiat 
ing  cavities,  whether  simple  or  ramified,  diverge  toward  the  peri 
phery.  It  is  true  that  the  open  chambers  of  the  Polyps  are  here 
transformed  into  narrow  tubes,  by  the  thickening  of  the  dividing 
partitions,  or  in  other  words,  the  open  spaces  of  the  Polyps  cor 
respond  to  tubes  in  the  Acalephs,  while  the  partitions  in  the 
Polyps  correspond  to  the  thick  masses  of  the  body  dividing  the 
tubes  in  the  Acalephs ;  but  the  principle  of  radiation  on  which 
the  whole  branch  of  Radiates  is  constructed  controls  the  organi 
zation  of  Acalephs  no  less  than  that  of  the  other  classes,  so  that 
a  transverse  section  across  any  Polyp  (Fig.  1),  or  across  any 
Acaleph  (Fig.  50),  or  across  any  Echinoderm  (Fig.  140),  shows 
their  internal  structure  to  be  based  upon  a  radiation  of  all  parts 
from  the  centre  to  the  periphery. 

That  there  may  be  no  vagueness  as  to  the  terms  used  here 
after,  we  would  add  one  word  respecting  the  nomenclature  of  this 
class,  whose  aliases  might  baffle  the  sagacity  of  a  police  detective. 
The  names  Acalephs,  Medusae,  or  the  more  common  appellation 
of  Jelly-fishes,  cover  the  same  ground,  and  are  applied  indiscrim 
inately  to  the  animals  they  represent.  The  name  Jelly-fish  is  an 
inappropriate  one,  though  the  gelatinous  consistency  of  these 
animals  is  accurately  enough  expressed  by  it ;  but  they  have  no 
more  structural  relation  to  a  fish  than  to  a  bird  or  an  insect. 


GENERAL   SKETCH   OF   ACALEPHS.  25 

They  have,  however,  received  this  name  before  the  structure  of 
animals  was  imderstood,  when  all  animals  inhabiting  the  waters 
were  indiscriminately  called  fishes,  and  it  is  now  in  such  general 
use  that  it  would  be  difficult  to  change  it.  The  name  Medusa  is 
derived  from  their  long  tentacular  appendages,  sometimes  wound 
up  in  a  close  coil,  sometimes  thrown  out  to  a  great  distance, 
sometimes  but  half  unfolded,  and  aptly  enough  compared  to  the 
snaky  locks  of  Medusa.  Their  third  and  oldest  appellation,  that  of 
Acalephs,  —  alluding  to  their  stinging  or  nettling  property,  and 
given  to  them  and  like  animals  by  Aristotle,  in  the  first  instance, 
but  afterwards  applied  by  Cuvier  in  a  more  limited  sense  to 
Jelly-fishes,  —  is  the  most  generally  accepted,  and  perhaps  the 
most  appropriate  of  all. 

The  subject  of  nomenclature  is  not  altogether  so  dry  and 
arid  as  it  seems  to  many  who  do  not  fully  understand  the  signifi 
cance  of  scientific  names.  Not  only  do  they  often  express  with 
terse  precision  the  character  of  the  animal  or  plant  they  signify, 
but  there  is  also  no  little  sentiment  concealed  under  these  jaw- 
breaking  appellations.  As  seafaring  men  call  their  vessels  after 
friends  or  sweethearts,  or  commemorate  in  this  way  some  impres 
sive  event,  or  some  object  of  their  reverence,  so  have  naturalists, 
under  their  fabrication  of  appropriate  names,  veiled  many  a  grace 
ful  allusion,  either  to  the  great  leaders  of  our  science,  or  to  some 
more  intimate  personal  affection.  The  Linncea  borealis  was  well 
named  after  his  famous  master,  by  a  disciple  of  the  great  Nor 
wegian  naturalist ;  G-oethea  semper flor ens,  the  ever-blooming,  is 
another  tribute  of  the  same  kind,  while  the  pretty,  graceful  little 
Lizzia,  named  by  Forbes,  is  one  instance  among  many  of  a  more 
affectionate  reference  to  nearer  friends.  The  allusions  of  this 
kind  are  not  always  of  so  amiable  a  character,  however,  —  witness 
the  "  Buffonia,"  a  low,  noxious  weed,  growing  in  marshy  places, 
and  named  by  Linnaeus  after  Buffon,  whom  he  bitterly  hated. 
Indeed,  there  is  a  world  of  meaning  hidden  under  our  zoological 
and  botanical  nomenclature,  known  only  to  those  who  are  inti 
mately  acquainted  with  the  annals  of  scientific  life  in  its  social  as 
well  as  its  professional  aspect. 


26  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 


CTENOPHOR^]. 

THE  Ctenopliorse  differ  from  other  Jelly-fishes  in  their  mode  of 
locomotion.  All  the  Discophorous  Medusae,  as  well  as  Hydroids, 
move  by  a  rhythmical  rise  and  fall  of  the  disk,  contracting  and 
expanding  with  alternations  so  regular,  that  it  reminds  one  of  the 
action  of  the  lungs,  and  seems  at  first  sight  to  be  a  kind  of  res 
piration  in  which  water  takes  the  place  of  air.  The  Greeks  rec 
ognized  this  peculiar  character  in  their  name,  for  they  called 
them  Sea-lungs.  Indeed,  locomotion,  respiration,  and  circulation 
are  so  intimately  connected  in  all  these  lower  animals,  that  what 
ever  promotes  one  of  these  functions  affects  the  other  also,  and 
though  the  immediate  result  of  the  contraction  and  expansion 
of  the  disk  seems  to  be  to  impel  them  through  the  water,  yet 
it  is  also  connected  with  the  introduction  of  water  into  the  body, 
which  there  becomes  assimilated  with  the  food  in  the  process  of 
digestion,  and  is  circulated  throiighout  all  its  parts  by  means  of 
ramifying  tubes.  In  the  Ctenophoras  there  is  no  such  regular 
expansion  and  contraction  of  the  disk  ;  they  are  at  once  dis 
tinguished  from  the  Discophorse  by  the  presence  of  external 
locomotive  appendages  of  a  very  peculiar  character.  They  move 
by  the  rapid  napping  of  countless  little  oars  or  paddles,  arranged 
in  vertical  rows  along  the  surface  of  the  disk,  acting  indepen 
dently  of  each  other  ;  one  row,  or  even  one  paddle,  moving  singly, 
or  all  of  them  together,  at  the  will  of  the  animal ;  thus  ena 
bling  it  to  accelerate  or  slacken  its  movements,  to  dart  through 
the  water  rapidly,  or  to  diminish  its  speed  by  partly  furling  its 
little  sails,  or,  spreading  them  slightly,  to  poise  itself  with  a  faint, 
quivering  movement  that  reminds  one  of  the  pause  of  the  hum 
ming-bird  in  the  air,  —  something  that  is  neither  positive  motion, 
nor  actual  rest.* 

These  locomotive  appendages  are  intimately  connected  with 
the  circulating  tubes,  as  we  shall  see  when  we  examine  the  struc- 

*  The  flappers  of  one  side  are  sometimes  in  full  activity,  while  those  of  the  other 
side  are  perfectly  quiet  or  nearly  so,  thus  producing  rotatory  movements  in  every 
direction. 


PLEUROBRACHIA.  27 

tural  details  of  these  animals,  so  that  in  them  also  breathing  and 
moving  are  in  direct  relation  to  each  other.  To  those  unaccus 
tomed  to  the  comparison  of  functions  in  animals,  the  use  of  the 
word  breathing,  as  applied  to  the  introduction  of  water  into  the 
body,  may  seem  inappropriate,  but  it  is  by  the  absorption  of 
aerated  water  that  these  lower  animals  receive  that  amount  of 
oxygen  into  the  system,  as  necessary  to  the  maintenance  of  life  in 
them,  as  a  greater  supply  is  to  the  higher  animals.  The  name 
of  Ctenophoras  or  comb-bearers,  is  derived  from  these  rows  of 
tiny  paddles  which  have  been  called  combs  by  some  naturalists, 
because  they  are  set  upon  horizontal  bands  of  muscles,  see  Fig. 
29,  reminding  one  of  the  base  of  a  comb,  while  the  fringes  are 
compared  to  its  teeth.  These  flappers  add  greatly  to  the  beauty 
of  these  animals,  for  a  variety  of  brilliant  hues  is  produced  along 
each  row  by  the  decomposition  of  the  rays  of  light  upon  them 
when  in  motion.  They  give  off  all  the  prismatic  colors,  and  as 
the  combs  are  exceedingly  small,  so  that  at  first  sight  one 
hardly  distinguishes  them  from  the  disk  itself,  the  exquisite  play 
of  color,  rippling  in  regular  lines  over  the  surface  of  the  animal, 
seems  at  first  to  have  no  external  cause. 

Pleurobrachia.     (Pleurobrachia  rJiododactyla  AG.) 

Among  the  most  graceful  and  attractive  of  these  animals  are 
the  Pleurobrachia  (Fig.  29),  and,  though  not  first  in  order,  we 
will  give  it  the  precedence  in  our  description,  because  it  will 
serve  to  illustrate  some  features  of  the  other  two  groups.  The 
body  of  the  Pleurobrachia  consists  of  a  transparent  sphere,  vary 
ing,  however,  from  the  perfect  sphere  in  being  somewhat  ob 
long,  and  also  by  a  slight  compression  on  two  opposite  sides 
(Figs.  27  and  28),  so  as  to  render  its  horizontal  diameter  longer 
in  one  direction  than  in  the  other  (Fig.  30). 
This  divergence  from  the  globular  form,  so  slight 
in  Pleurobrachia  as  to  be  hardly  perceptible  to 
the  casual  observer,  establishing  two  diameters  of 
different  lengths  at  right  angles  with  each  other, 
is  equally  true  of  the  other  genera.  It  is  inter 
esting  and  important,  as  showing  the  tendency  in 

Fig.  27.    Pleurobrachia  seen  at  right  angles  to  the  plane  In  which  the  tentacles  are  placed.  (Ayassiz.) 


28  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

this  highest  group  of  Acalephs  to  assume  a  bi 
lateral  character.  This  bilaterality  becomes  still 
more  marked  in  the  highest  class  of  Radiates,  the 
Echinoderms.  Such  structural  tendencies  in  the 
\8  |H|5fei  Jjl  lower  animals,  hinting  at  laws  to  be  more  fully 
developed  in  the  higher  forms,  are  always  signifi 
cant,  as  showing  the  intimate  relation  between  all 
parts  of  the  plan  of  creation.  This  inequality  of 
the  diameters  is  connected  with  the  disposition  of  parts  in  the 
whole  structure,  the  locomotive  fringes  and  the  vertical  tubes 
connected  with  them  being  arranged  in  sets  of  four  on  either  side 
of  a  plane  passing  through  the  longer  diameter,  showing  ,thus  a 
tendency  toward  the  establishment  of  a  right  and  left  side  of  the 
body,  instead  of  the  perfectly  equal  disposition  of  parts  around  a 
common  centre,  as  in  the  lower  Radiates. 

The  Pleurobrachia  are  so  transparent,  that,  with  some  prepara 
tory  explanation  of  their  structure,  the  most  unscientific  observer 
may  trace  the  relation  of  parts  in  them.  At  one  end  of  the  sphere 
is  the  transverse  split  (Fig.  27),  that  serves  them  as  a  mouth  ;  at 
the  opposite  pole  is  a  small  circumscribed  area,  in  the  centre 
of  which  is  a  dark  eye-speck.  The  eight  rows  of  locomotive 
fringes  run  from  pole  to  pole,  dividing  the  whole  surface  of  the 
body  like  the  ribs  on  a  melon.  (Figs.  27,  28.)  Hanging  from 
either  side  of  the  body,  a  little  above  the  area  in  which  the  eye- 
speck  is  placed,  are  two  most  extraordinary  appendages  in  the 
shape  of  long  tentacles,  possessing  such  wonderful  power  of  ex 
tension  and  contraction  that,  while  at  one  moment  they  may  be 
knotted  into  a  little  compact  mass  no  bigger  than  a  pin's  head, 
drawn  up  close  against  the  side  of  the  body,  or  hidden  within  it, 
the  next  instant  they  may  be  floating  behind  it  in  various  posi 
tions  to  a  distance  of  half  a  yard  and  more,  putting  out  at  the 
same  time  soft  plumy  fringes  (Fig.  29)  along  one  side,  like  the 
beard  of  a  feather.  One  who  has  never  seen  these  animals  may 
well  be  pardoned  for  doubting  even  the  most  literal  and  matter- 
of-fact  account  of  these  singular  tentacles.  There  is  no  variety 
of  curve  or  spiral  that  does  not  seem  to  be  represented  in  their 
evolutions.  Sometimes  they  unfold  gradually,  creeping  out  softly 

Fig.  23.    Pleurobrachia  seen  in  plane  of  tentacles.    (Agassiz.) 


PLEUKOBRACHIA. 


29 


Fig.  29. 


and  slowly  from  a  state  of  contraction,  or  again  the  little  ball, 
hardly  perceptible  against  the  side  of  the  body,  drops  suddenly 
to  the  bottom  of 
the  tank  in  which 
the  animal  is  float 
ing,  and  one  thinks 
for  a  moment,  so 
slight  is  the  thread 
like  attachment, 
that  it  has  actual 
ly  fallen  from  the 
body ;  but  watch  a 
little  longer,  and 
all  the  filaments 
spread  out  along 
the  side  of  the 
thread,  it  expands 
to  its  full  length 
and  breadth,  and  resumes  all  its  graceful  evolutions. 

One  word  of  the  internal  structure  of  these  animals,  to  explain 
its  relation  to  the  external  appendages.  The  mouth  opens  into  a 
wide  digestive  cavity  (Figs.  27,  28),  enclosed  between  two  verti 
cal  tubes.  Toward  the  opposite  end  of  the  body  these  tubes 
terminate  or  unite  in  a  single  funnel-like  canal,  which  is  a  reser 
voir  as  it  were  for  the  circulating  fluid  poured  into  it  through  an 
opening  in  the  bottom  of  the  digestive  cavity.  The  food  in  the 
digestive  cavity  becomes  liquefied  by  mingling  with  the  water 
entering  with  it  at  the  mouth,  and,  thus  prepared,  it  passes  into 
this  canal,  from  which,  as  we  shall  presently  see,  all  the  circulat 
ing  tubes  ramifying  throughout  the  body  are  fed.  Two  of  these 
circulating  tubes,  or,  as  they  are  called  from  the  nature  of  the 
liquid  they  contain,  chymiferous  tubes,  are  very  large,  starting 
horizontally  and  at  right  angles  with  the  digestive  cavity  from 
the  point  of  junction  between  the  vertical  tubes  (Fig.  30)  and 
the  canal.  Presently  they  give  off  two  branches,  these  again 
ramifying  in  two  directions  as  they  approach  the  periphery,  so 
that  each  one  of  the  first  main  tubes  has  multiplied  to  four, 


Fig.  29.    Natural  attitude  of  Pleurobrachia  when  in  motion. 


30  MARINE   ANIMALS    OF    MASSACHUSETTS    BAY. 

before  its  ramifications  reach  the  surface,  thus  making  in  all 

eight  radiating  tubes.  So  far,  these 
eight  tubes  are  horizontal,  all  diverging 
on  the  same  level ;  but  as  they  reach 
the  periphery  each  one  gives  rise  to 
a  vertical  tube,  running  along  the  sur 
face  of  the  body  from  pole  to  pole,  just 
within  the  rows  of  locomotive  fringes 
on  the  outer  surface,  and  immediately 
connected  with  them  (Figs.  27, 28).  As 
in  all  the  Ctenophorae,  these  fringes  keep 

up  a  constant  play  of  color  by  their  rapid  vibrations.  In  Pleuro- 
brachia  the  prevailing  tint  is  a  yellowish  pink,  though  it  varies  to 
green,  red,  and  purple,  with  the  changing  motions  of  the  animal. 
We  have  seen  that  the  vertical  tubes  between  which  the  digestive 
cavity  is  enclosed,  start  like  the  cavity  itself  from  that  pole  of  the 
body  where  the  mouth  is  placed,  and  that,  as  they  approach  the 
opposite  pole,  at  a  distance  from  the  mouth  of  about  two  thirds 
the  whole  length  of  the  body,  they  unite  in  the  canal,  which  then 
extends  to  the  other  pole  where  the  eye-speck  is  placed.  As  it  is 
just  at  this  point  of  juncture  between  the  tubes  and  the  canal 
that  the  two  main  horizontal  tubes  arise  from  which  all  the 
others  branch  on  the  same  plane  (Figs.  27,  28),  it  follows 
that  they  reach  the  periphery,  not  on  a  level  with  the  pole  op 
posite  the  mouth,  but  removed  from  it  by  about  one  third  the 
height  of  the  body.  In  consequence  of  this  the  eight  vertical 
tubes  arising  from  the  horizontal  ones,  in  order  to  run  the  entire 
length  of  the  body  from  pole  to  pole,  extend  in  opposite  direc 
tions,  sending  a  branch  to  each  pole,  though  the  branch  running 
toward  the  mouth  is  of  course  the  longer  of  the  two.  The  tenta 
cles  have  their  roots  in  two  sacs  within  the  body,  placed  at  right 
angles  with  the  split  of  the  mouth.  (Figs.  27,  30.)  They  open 
at  the  surface  on  the  opposite  side  from  the  mouth,  though  not 
immediately  within  the  area  at  which  the  eye-speck  is  placed, 
but  somewhat  above  it,  and  at  a  little  distance  on  either  side  of  it. 
The  tentacles  may  be  drawn  completely  within  these  sacs,  or  be 
extended  outside,  as  we  have  seen,  to  a  greater  or  less  degree,  and 
in  every  variety  of  curve  or  spiral. 

Fig.  30.    Pleurobrachia  seen  from  the  extremity  opposite  the  mouth. 


BOLINA. 


31 


Bolina.     {Bolina  alata  Ac.) 

THE  Bolina  (Fig  32),  like  the  Pleurobrachia,  is  slightly  oval  in 
form,  with  a  longitudinal  split  at  one  end  of  the  body,  forming  a 
month  which  opens  into  a  capacious  sac  or  digestive  cavity. 
But  it  differs  from  the  Pleurobrachia  in  having  the  oral  end  of 
the  body  split  into  two  larger  lobes  (Fig.  31),  hanging  down 
from  the  mouth.  These  lobes  may  gape  rifr  31 

widely,  or  they  may  close  completely 
over  the  mouth  so  as  to  hide  it  from 
view,  and  their  different  aspects  under 
various  degrees  of  expansion  or  contrac 
tion  account  for  the  discrepancies  in  the 
description  of  these  animals.  We  have 
seen  that  the  Pleurobrachia  moves 
with  the  mouth  upward ;  but  the  Bo 
lina,  on  the  contrary,  usually  carries 
the  mouth  downward,  though  it  occasionally  reverses  its  position, 
and  in  this  attitude,  with  the  lobes  spread  open,  it  is  exceedingly 
graceful  in  form,  and  looks  like  a  white  flower  with  the  crown 
fully  expanded.  These  broad  lobes  are  balanced  on  the  other 
sides  of  the  body  by  four  smaller  appendages,  divided  in  pairs, 
two  011  each  side  (Fig.  32),  called  auricles.  These  so-called 
aiiricles  are  in  fact  organs  of  the  same  kind 
as  the  larger  lobes,  though  less  developed. 
The  rows  of  locomotive  flappers  on  the  Bo 
lina  differ  in  length  from  each  other  (Fig. 
31),  instead  of  being  equal,  as  in  the  Pleu 
robrachia.  The  four  longest  ones  are  op 
posite  each  other  on  those  sides  of  the  body 
where  the  larger  lobes  are  developed,  the 
four  short  ones  being  in  pairs  on  the  sides 
where  the  auricles  are  placed.  At  first  sight 
they  all  seem  to  terminate  at  the  margin  of  the  body,  but  a  closer 

Fig.  31.  Bolina  seen  from  the  broad  side  ;  o  eye-speck,  m  mouth,  r  auricles,  v  digestive  cavity,  g  h 
short  rows  of  flappers,  af  long  rows  of  flappers,  nxtz  tubes  winding  in  the  larger  lobes; about  half 
natural  size.  (Ayassiz.) 

Fig.  32.  Bolina  seen  from  the  narrow  side  ;  c  h  short  rows  of  flappers,  a  b  long  rows  of  flappers  ; 
other  letters  as  in  Fig.  31.  (Acjassiz.) 


Fig.  32. 


32  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

examination  shows  that  the  circulating  tubes  connected  with  the 
longer  row  extend  into  the  lobes,  where  they  wind  about  in  a 
variety  of  complicated  involutions.  (Fig.  32.)  The  movements 
of  the  Bolina  are  more  sluggish  than  those  of  the  Pleurobrachia, 
and  the  long  tentacles,  so  graceful  an  ornament  to  the  latter,  are 
wanting  in  the  former.  With  these  exceptions  the  description 
given  above  of  the  Pleurobrachia  will  serve  equally  well  for  the 
Bolina.  The  structure  is  the  same  in  all  essential  points,  though 
it  differs  in  the  size  and  proportion  of  certain  external  features, 
and  its  play  of  color  is  less  brilliant  than  that  of  the  Pleuro 
brachia.  The  Bolina,  with  its  slow,  undulating  motion,  its  broad 
lobes  sometimes  spreading  widely,  at  other  times  folded  over  the 
mouth,  its  delicacy  of  tint  and  texture,  and  its  rows  of  vibrating 
fringes  along  the  surface,  is  nevertheless  a  very  beautiful  object, 
and  well  rewards  the  extreme  care  without  which  it  dies  at  once 
in  confinement. 

Idyitt.     (Idyia  roseola  AG.) 

The  lowest  genus  of  Ctenophorse  found  on  our  coast,  the  Idyia 
(Fig.  33) ,  has  neither  the  tentacles  of  the  Pleurobrachia,  nor  the 
lobes  of  the  Bolina.  It  is  a  simple  ovate  sphere,  the  interior  of 
which  is  almost  entirely  occupied  by  an  immense  digestive  cavity. 
It  would  seem  that  the  reception  and  digestion  of  food  is  intended 
33  to  be  the  almost  exclusive  function  of  this 

animal,  for  it  has  a  mouth  whose  ample  di 
mensions  correspond  with  its  capacious  stom 
ach.  Instead  of  the  longitudinal  split  serving 
as  a  mouth,  in  the  Bolina  and  Pleurobrachia, 
one  end  of  the  body  in  the  Idyia  is  completely 
open  (Fig.  33),  so  that  occasionally  some  un 
suspicious  victim  of  smaller  diameter  than 
itself  may  be  seen  to  swim  into  this  wide  por 
tal,  when  suddenly  the  door  closes  behind  him 
with  a  quick  contraction,  and  he  finds  himself  a  prisoner.  The 
Idyia  does  not  always  obtain  its  food  after  this  indolent  fashion 

Fig.  33      Idyia  roseola  seen  from  the  broad  side,  half  natural  size  ;  a  anal  opening,  b  lateral  tube,  c 
circular  tube,  d  efg  h  rows  of  locomotive  flappers.     ( Ayassiz.) 


IDYIA.  33 

however,  for  it  often  attacks  a  Bolina  or  Pleurobrachia  as  large 
or  even  larger  than  itself,  when  it  extends  its  mouth  to  the  ut 
most,  slowly  overlapping  the  prey  it  is  trying  to  swallow  by  fre 
quent  and  repeated  contractions,  and  even  cutting  off  by  the 
same  process  such  portions  as  cannot  be  forced  into  the  digestive 
cavity. 

The  general  internal  structure  of  the  Idyia  corresponds  with 
that  of  the  Bolina  and  Pleurobrachia  ;  it  has  the  same  tubes 
branching  horizontally  from  the  main  cavity,  then  ramifying  as 
they  approach  the  periphery  till  they  are  multiplied  to  eight  in 
all,  each  of  which  gives  off  one  of  the  vertical  tubes  connected 
with  the  eight  rows  of  locomotive  flappers.  Opposite  the  mouth 
is  the  eye-speck,  placed  as  in  the  two  other  genera,  at  the  centre 
of  a  small  circumscribed  area,  which  in  the  Idyia  is  surrounded 
by  delicate  fringes,  forming  a  rosette  at  this  end  of  the  body. 
These  animals  are  exceedingly  brilliant  in  color  ;  bright  pink  is 
their  prevailing  hue,  though  pink,  red,  yellow,  orange,  green, 
and  purple,  sometimes  chase  each  other  in  quick  succession  along 
their  locomotive  fringes.  At  certain  seasons,  when  most  numer 
ous,  they  even  give  a  rosy  tinge  to  patches  on  the  surface  of  the 
sea.  Their  color  is  brightest  and  deepest  before  the  spawning 
season,  but  as  this  advances,  and  the  ovaries  and  spermaries  are 
emptied,  they  grow  paler,  retaining  at  last  only  a  faint  pink  tint. 
They  appear  early  in  July,  rapidly  attain  their  maximum  size, 
and  are  most  numerous  during  the  first  half  of  August.  Toward 
the  end  of  August  they  spawn,  and  the  adults  are  usually  de 
stroyed  by  the  early  September  storms,  the  young  disappearing 
at  the  same  time,  not  to  be  seen  again  till  the  next  summer.  It 
is  an  interesting  question,  not  yet  solved,  to  know  what  becomes 
of  the  summer's  brood  in  the  following  winter.  They  probably 
sink  into  deep  waters  during  this  intervening  period.  The  Idyia, 
like  the  Pleurobrachia,  moves  with  the  mouth  upward,  but  in 
clined  slightly  forward  also,  so  as  to  give  an  oblique  direction  to 
the  axis  of  the  body.* 

*  Until  this  summer  only  the  three  genera  of  Ctenophorae  above  mentioned  were 

supposed  to  exist  along  our  coast,  but  during  the  present  season  I  have  had  the  good 

fortune  to  find  two  additional  ones.    One  of  them,  the  Lesueuria,  resembles  a  Bolina 

with  the  long  lobes  so  cut  off,  that  they  have  a  very  stunted  appearance  in  compari- 

5 


34  MARINE   ANIMALS    OF   MASSACHUSETTS   BAY. 


EMBRYOLOGY  OF  CTENOPHORAE. 

ALL  the  Ctenophorae  are  reproduced  from  eggs,  these  eggs 
being  so  transparent  that  one  may  follow  with  comparative  ease 
the  changes  undergone  by  the  young  while  still  within  the  egg 
envelope.  Unfortunately,  however,  they  are  so  delicate  that  it  is 
impossible  to  keep  them  alive  for  any  length  of  time,  even  by 
supplying  them  constantly  with  fresh  sea-water,  and  keeping 
them  continually  in  motion,  both  of  which  are  essential  conditions 
to  their  existence.  It  is  therefore  only  from  eggs  accidentally 
fished  up  at  different  stages  of  growth  that  we  may  hope  to  ascer 
tain  any  facts  respecting  the  sequence  of  their  development. 
When  hatched,  the  little  Ctenophore  is  already  quite  advanced. 
It  is  small  when  compared  with  the  size  of  the  egg  envelope,  and 
long  before  it  is  set  free,  it  swims  about  with  great  velocity  with 
in  the  walls  of  its  diminutive  prison  (Fig.  35).  The  importance 
of  studying  the  young  stages  of  animals  can  hardly  find  a  better 
illustration  than  among  the  Ctenophora3.  Before  their  extraor 
dinary  embryonic  changes  were  understood,  many  of  the  younger 
forms  had  found  their  way  into  our  scientific  annals  as  distinct 
animals,  and  our  nomenclature  thus  became  burdened  with 
long  lists  of  names  which  will  disappear  as  our  knowledge  ad 
vances. 

The  great  size  of  their  locomotive  flappers  in  proportion  to  the 
rest  of  the  body,  is  characteristic  of  the  young  Ctenophorae. 
They  seem  like  large  paddles  on  the  sides  of  these  tiny  trans 
parent  spheres,  and,  owing  to  their  great  power  as  compared  with 
those  of  the  adult,  the  young  move  with  extraordinary  rapidity. 
The  Pleurobrachia  alone  retains  its  quickness  of  motion  in  after 
life,  and  although  its  long  graceful  streamers  appear  only  as  short 
stumpy  tentacles  in  the  young  (Fig.  34),  yet  its  active  little  body 
would  be  more  easily  recognized  in  the  earlier  stages  of  growth 

son  with  those  of  the  Bolina.  The  other,  the  Mertensia,  is  closely  allied  to  Pleuro 
brachia  ;  it  is  exceedingly  flattened  and  pear-shaped.  This  species  was  discovered 
long  ago  by  Fabricius,  but  had  escaped  thus  far  the  attention  of  other  naturalists. 
(A.  Agassiz.) 


EMBRYOLOGY  OF  CTENOPHOR^E. 


35 


than  that  of  the  other  Ctenophorae.  Figs.  34,  35,  and  36  show 
the  Pleurobrachia  at  various  stages  of  growth  ;  Fig.  34,  with  its 
thick  stunted  tentacles  and  short  rows  of  flappers,  is  the  youngest; 
the  flappers  themselves  are  rather  long  at  this  age,  looking  more 
like  stiff  hairs  than  like  the  minute  fringes  of  the  adult.  In  Fig. 

Fig.  34.  Fig.  35. 


35  the  tentacles  are  already  considerably  longer  and  more  deli 
cate  ;  in  Fig.  36  the  vertical  tubes  are  already  completed,  while 
Figs.  27-29  present  it  in  its  adult  condition. 

The  Idyia  differs  greatly  in  appearance  at  different  periods  of 

Fig.  36  Fig.  37. 


its  development,  and,  indeed,  no  one  would  suspect,  without  some 
previous  knowledge  of  its  transformations,  that  the  young  Idyia, 

Fig.  34.  Young  Pleurobrachia  still  in  the  egg ;  t  tentacles,  e  eye-speck,  c  c  rows  of  locomotive  flap 
pers,  d  digestive  cavity;  greatly  magnified. 

Fig.  36.    Young  Pleurobrachia  swimming  about  in  the  egg  just  before  hatching  ;  magnified. 

Fig.  36.  Young  Pleurobrachia  resembling  somewhat  the  adult ;  /funnel  leading  to  anal  opening,  I 
lateral  tubes,  c  c  c'  c1  rows  of  locomotive  flappers;  magnified. 

Fig.  37.     Young  Idyia,  greatly  magnified  ;  lettering  as  in  Fig.  36  ;  d  digestive  cavity. 


36 


MARINE    ANIMALS    OF   MASSACHUSETTS    BAY. 


with  its  rapid  gyrations,  its  short  ambnlacral  tubes,  like  immense 
pouches  (Fig.  37),  its  large  pigment  spots  scattered  over  the  sur 
face  (Fig.  38),  was  an  earlier  stage  of  the  rosy-hued  Idyia,  which 
glides  through  the  water  with  a  scarcely  perceptible  motion. 

Fig.  38.  Fig.  39. 


Fig.  40. 


Figs.  37-40  represent  the  various  stages  of  its  growth.  It  will 
be  seen  how  very  short  are  the  locomotive  fringes  (Fig.  39)  in 
comparison  with  those  of  the  full-grown  ones  (Fig.  33).  It  is 

only  in  the  adult  Idyia  that  these  rows 
attain  their  full  height,  and  the  tubes, 
ramifying  throughout  the  body  (Fig. 
40),  are  completed. 

The  Bolina,  in  its  early  condition, 
recalls  the  young  Pleurobrachia. 
At  this  period  it  has  the  same  rapid 
motion,  and  when  somewhat  more 
advanced,  long  tentacles,  resembling 
those  of  the  Pleurobrachia,  make 
their  appearance  (Fig.  41)  ;  it  is  only 
at  a  later  period  that  the  tentacles 
become  contracted,  while  the  large 
lobes  (Fig.  42),  so  characteristic  of 

Bolina,  are  formed  by  the  elongation  of  the  oral  end  of  the 
body,  the  auricles  becoming  more  conspicuous  at  the  same 

Fig.  38.  Young  Idyia  seen  from  the  anal  extremity,  magnified  5  a  anal  opening,  other  letters  as  in 
Fig.  36. 

Fig.  39.  Idyia  somewhat  older  than  Fig.  37,  lettering  as  before  ;  magnified. 

Fig.  40.  Young  Idyia  in  which  the  ambulacral  tubes  begin  to  ramify  ;  magnified,  letters  as  before. 


DISCOPHOILE.  37 

time  (Fig.  43).  A  little  later  the  lobes  enlarge,  the  movements 
become  more  lazy ;  it  assumes  both  in  form  and  habits  the  char 
acter  of  the  adult  Bolina. 

The  series  of  changes  through  which  the   Ctenophoras   pass 

Fig.  41.  Fig.  42.  Fig.  43. 


are  as  remarkable  as  any  we  shall  have  occasion  to  describe, 
though  not  accompanied  with  such  absolutely  different  con 
ditions  of  existence.  The  comparison  of  the  earlier  stages  of 
life  in  these  animals  with  their  adult  condition  is  important, 
not  only  with  reference  to  their  mode  of  development,  but  also 
because  it  gives  us  some  insight  into  the  relative  standing  of  the 
different  groups,  since  it  shows  us  that  certain  features,  perma 
nent  in  the  lower  groups,  are  transient  in  the  higher  ones.  A 
striking  instance  of  this  occurs  in  the  fact  mentioned  above,  that 
though  the  long  tentacles  so  characteristic  of  the  adult  Pleuro- 
brachia  exist  in  the  young  Bolina,  they  yield  in  importance  at 
a  later  period  to  the  lobes  which  eventually  become  the  pre 
dominant  and  characteristic  feature  of  the  latter. 


DISCOPHOR^E. 

THE  disk  of  the  Discophorse  is  by  no  means  so  delicate  as  that 
of  the  other  Jelly-fishes.  It  seems  indeed  quite  solid,  and  some 
what  like  cartilage  to  the  touch,  and  yet  so  large  a  part  of  its 
bulk  consists  of  water,  that  a  Cyanea,  weighing  when  alive  about 
thirty-four  pounds,  being  left  to  dry  in  the  sun  for  some  days,  was 

Fig.  41.    Young  Bolina  in  stage  resembling  Pleurobrachia ;  greatly  magnified. 

Fig.  42.    Young  Bolina  seen  from  the  broad  side,  with  rudimentary  auricles  and  lobes;  magnified. 

Fig.  43.    The  same  as  Fig.  42,  seen  from  the  narrow  side. 


38  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

found  to  have  lost  about  -f^j  of  its  original  weight,  —  only  the 
merest  film  remaining  on  the  paper  upon  which  it  had  been  laid. 
The  prominence  of  the  disk  in  this  group  of  Jelly-fishes  is  well 
characterized  by  their  German  name,  "  Scheiben  quallen,"  viz. 
disk-medusae.  We  shall  see  hereafter  that  the  disk,  so  large  and 
seemingly  solid  in  the  Discophorae,  thins  out  in  many  of  the  other 
Jelly-fishes,  and  becomes  exceedingly  concave.  This  is  especially 
the  case  in  many  of  the  Hydroid  Medusae,  where  it  assumes  a 
bell-shaped  form,  and  is  constantly  spoken  of  as  the  bell.  It 
should  be  remembered,  however,  in  reading  descriptions  of  these 
animals,  that  the  so-called  bell  is  only  a  modified  disk,  and  per 
fectly  homologous  with  that  organ  in  the  Discophorae. 

The  Discophorous  Medusae  are  distinguished  from  all  others  by 
the  peculiar  nature  of  the  reproductive  organs.  They  are  con 
tained  in  pouches  (Fig.  50,  0,0,0,0),  the  contents  of  which  are 
first  discharged  into  the  main  cavity,  and  then  pass  out  through 
the  mouth.  Pillars  support  the  four  angles  of  the  digestive 
cavity,  thus  separating  the  lower  from  the  upper  floor  of  the  disk, 
while  the  chymiferous  tubes  (Fig.  50)  branch  and  run  into 
each  other  near  the  periphery,  forming  a  more  or  less  compli 
cated  anastomosing  network,  instead  of  a  simple  circular  tube,  as 
is  the  case  with  the  Hydroid  Medusae.  (Fig.  74.) 

Cyanea.     (Cyanea  arctica  PER.  et  LES.) 

In  our  descriptions  of  the  Discophorae,  we  may  give  the  pre 
cedence  to  the  Cyanea  on  account  of  its  size.  This  giant  among 
Jelly-fishes  is  represented  in  Fig.  44.  It  is  much  to  be  regretted 
that  these  animals,  when  they  are  not  so  small  as  to  escape  atten 
tion  altogether,  are  usually  seen  out  of  their  native  element, 
thrown  dead  or  dying  on  the  shore,  a  mass  of  decaying  gelatinous 
matter.  All  persons  who  have  lived  near  the  sea  are  familiar 
with  the  so-called  Sea-blubbers,  sometimes  strewing  the  sandy 
beaches  after  the  autumn  storms  in  such  numbers  that  it  is  diffi 
cult  to  avoid  them  in  walking  or  driving.  In  such  a  condition 
the  Cyanea  is  far  from  being  an  attractive  object ;  to  form  an 
idea  of  his  true  appearance,  one  must  meet  him  as  he  swims 
along  at  midday,  rather  lazily  withal,  his  huge  semi-transparent 


CYANEA.  39 

disk,  with  its  flexible  lobed  margin,  glittering  in  the  sun,  and  his 
tentacles  floating  to  a  distance  of  many  yards  behind  him.  En 
countering  one  of  those  huge  Jelly-fishes,  when  out  in  a  row- 
boat  one  day,  we  attempted  to  make  a  rough  measurement  of  his 
dimensions  upon  the  spot.  He  was  lying  quietly  near  the  sur 
face,  and  did  not  seem  in  the  least  disturbed  by  the  proceeding, 
but  allowed  the  oar,  eight  feet  in  length,  to  be  laid  across  the 
disk,  which  proved  to  be  about  seven  feet  in  diameter.  Backing 
the  boat  slowly  along  the  line  of  the  tentacles,  which  were  float 
ing  at  their  utmost  extension  behind  him,  we  then  measured 
these  in  the  same  manner,  and  found  them  to  be  rather  more 
than  fourteen  times  the  length  of  the  oar,  thus  covering  a  space 
of  some  hundred  and  twelve  feet.  This  sounds  so  marvellous 
that  it  may  be  taken  as  an  exaggeration ;  but  though  such  an 
estimate  could  not  of  course  be  absolutely  accurate,  yet  the  facts 
are  rather  understated  than  overstated  in  the  dimensions  here 
given.  And,  indeed,  the  observation  was  more  careful  and  pre 
cise  than  the  circumstances  would  lead  one  to  suppose,  for  the 
creature  lay  as  quietly,  while  his  measure  was  taken,  as  if  he  had 
intended  to  give  every  facility  for  the  operation.  This  specimen 
was,  however,  of  unusual  size  ;  they  more  commonly  measure 
from  three  to  five  feet  across  the  disk,  while  the  tentacles  may 
be  thirty  or  forty  feet  long.  The  tentacles  are  exceedingly 
numerous  (see  Fig.  44),  arising  in  eight  distinct  bunches,  from 
the  margin  of  the  disk,  and  hanging  down  in  a  complete  laby 
rinth. 

These  animals  are  not  so  harmless  as  it  would  seem,  from 
their  soft,  gelatinous  consistency ;  it  is  no  pleasant  thing  when 
swimming  or  bathing  to  "become  entangled  in  this  forest  of  fine 
feelers,  for  they  have  a  stinging  property  like  nettles,  and  may 
render  a  person  almost  insensible,  partly  from  pain,  and  partly 
from  a  numbness  produced  by  their  contact,  before  he  is  able  to 
free  himself  from  the  network  in  which  he  is  caught.  The 
weapons  by  which  they  produce  these  results  seem  so  insignifi 
cant,  that  one  cannot  but  wonder  at  their  power.  The  tentacles 
are  covered  by  minute  cells,  lasso-cells  as  they  are  called,  (simi 
lar  to  those  of  Astrangia,  Fig.  19,)  each  one  of  which  contains 
a  whip  finer  than  the  finest  thread,  coiled  in  a  spiral  within  it. 


Fig.  44.    Cyanea  arctica  ;  greatly  reduced  in  size. 


CYANEA. 


41 


These  myriad  whips  can  be  thrown  out  at  the  will  of  the  animal, 
and  really  form  an  efficient  galvanic  battery.  Behind  the  veil 
of  tentacles,  and  partly  hidden  by  it,  four  curtains,  with  lobed  or 
ruffled  margins,  dimly  seen  in  Fig.  44,  hang  down  from  the  un 
der  surface  of  the  disk.  The  ovaries  are  formed  by  four  pendent 
pouches,  placed  near  the  sides  of  the  mouth,  and  attached  to  four 
cavities  within  the  disk.  Around  the  circumference  of  the  disk 
are  eight  eye-specks,  each  formed  by  a  small  tube  protected  un 
der  a  little  lappet  or  hood  rising  from  the  upper  surface  of  the 
disk.  The  prevailing  color  of  this  huge  Jelly-fish  is  a  dark 
brownish-red,  with  a  light,  milk-white  margin,  tinged  with  blue, 
the  tentacles  and  other  pendent  appendages  having  a  some 
what  different  hue  from  the  disk.  The  ovaries  are  flesh-col 
ored,  the  curtain  formed  by  the  expansion  of  the  lobes  of  the 
mouth  is  dark  brown,  while  the  tentacles  are  of  different  colors, 
some  being  yellow,  others  purple,  and  others  reddish  brown  or 
pink. 

Strange  to  say,  this  gigantic  Discophore  is  produced  by  a  Hy- 
droid  measuring  not  more  than  half  an  inch  in  height  when  full 
grown ;  could  we  follow  the  history  of  any  egg  laid  by  one  of 
these  Discophorse  in  the  autumn,  which  has  indeed  been  par- 


Fig.  45. 


Fig.  46 


tially  done,  we  should  see  that,  like  any  other  planula,  the  young 
hatched  from  the  egg  is  at  first  spherical,  but  presently  becomes 
pear-shaped,  and  attaches  itself  to  the  ground.  From  the  upper 


Fig.  45.     Scyphistoma  of  a  Discophore  ;  Aurelia  flavidula.   (Agassiz.) 
Fig.  46.    Scyphistoma,  older  than  Fig.  45.   (Agassiz.) 
Fig.  47.    Strobila  of  a  Discophore  ;  Aurelia  flavidula.   (Agassiz.) 
6 


42 


MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 


end  tentacles  project  (see  Fig.  45),  growing  more  numerous,  as 
in  Fig.  46,  though  they  never  exceed  sixteen  in  number.  As  it 
increases  in  height  constrictions  take  place  at  different  distances 
along  its  length,  every  such  constriction  being  lobed  around  its 
margin,  till  at  last  it  looks  like  a  pile  of  scalloped  saucers  or 
disks  strung  together  (see  Fig.  47).  The  topmost  of  these  disks 
Fig.  48.  falls  off  and  dies  ;  but  all  the  others  separate 

by  the  deepening  of  the  constrictions,  and 
swim  off  as  little  free  disks  (Fig.  48),  which 
eventually  grow  into  the  enormous  Jelly-fish 
described  above.  These  three  phases  of  growth, 
before  the  relation  between  them  was  under 
stood,  have  been  mistaken  for  distinct  animals, 
and  described  as  such  under  the  names  of  Scyphistoma,  Strobila, 
and  Ephyra. 


Fig.  49. 


Aurelia.     (Aurelia  flavidula  PER.  et  LES.) 

Another  large  Discophore,  though  by  no  means  to  be  compared 
to  the  Cyanea  in  size,  is  our  common  Aurelia  (Figs.  49,  50). 
Its  bluish- white  disk  measures  from  twelve  to  fifteen  inches  in 
diameter,  but  its  dimensions  are  not  increased  by  the  tentacles, 
which  have  no  great  power  of  contraction  and  expansion,  and 
form  a  short  fringe  around  its  margin,  widening  and  narrowing 

slightly  as  the  tentacles 
are  stretched  or  drawn 
in.  It  is  quite  trans 
parent,  as  may  be  seen 
in  Fig  49,  where  all  the 
fine  ramifications  of  the 
chymiferous  tubes,  as 
well  as  the  ovaries,  are 
seen  through  the  vault  of  the  disk.  Fig.  50  represents  the  upper 
surface,  with  the  ovaries  around  the  mouth,  occupying  the  same 
position  as  those  of  the  Cyanea,  though  they  differ  from  the  latter 
in  their  greater  rigidity,  and  do  not  hang  down  in  the  form  of 


Fig.  48.    Ephyra  of  a  Discophore  ;  Aurelia  flavidula.    (Ayassiz.) 
Fig.  49.    Aurelia  seen  in  profile,  reduced.   (Ayassiz.) 


AURELIA. 


43 


pouches.  The  males  and  females  in  this  kind  of  Jelly-fish  may 
be  distinguished  by  the  difference  of  color  in  the  reproductive 
organs,  which  are  rose-colored  in  the  males,  and  of  a  dull  yellow 
in  the  females.  The  process  of  development  is  exactly  the  same 
in  the  Aurelia  as  in  the  Cyanea,  though  there  is  a  very  slight 
difference,  in  their  respective  Hydroids.  They  are,  however,  so 
much  alike,  that  one  is  here  made  to  serve  for  both,  the  above 
figures  being  taken  from  the  Hydroid  of  the  Aurelia.  It  is 
curious,  that  while,  as  in  the  case  of  the  Aurelia  and  Cyanea, 
very  dissimilar  Jelly-fishes  may  arise  from  almost  identical  Hy- 

Fig.  50. 


droids,  we  have  the  reverse  of  the  proposition,  in  the  fact  that 
Hydroids  of  an  entirely  distinct  character  may  produce  similar 
Jelly-fishes. 

The  embryos  or  little  planula3,  hatched  from  the  Cyanea  and 
Aurelia  in  the  fall,  seem  to  be  gregarious  in  their  mode  of  life, 
swimming  about  together  in  great  numbers  till  they  find  a  suit 
able  point  of  attachment,  and  assume  their  fixed  Hydroid  exist 
ence.  The  Cyanea3,  however,  when  adult,  are  usually  found 
singly,  while  the  Aurelia3,  on  the  contrary,  seek  each  other,  and 
commonly  herd  together. 

Fig.  50.     Aurelia  flavidula,  seen  from  above  5  o  mouth,  e  e  e  e  eyes,  mm  mm  lobes  of  the  mouth, 
oo  oo  ovaries,  tttt  tentacles,  w  w  ramified  tubes.   (Agassiz.) 


44 


MARINE   ANIMALS    OF   MASSACHUSETTS   BAY. 


The  Campanella.     (Campanella  pachyderma  A.  AG.) 

The   Campanella   (Fig.    51)  is  a  pretty  little  Jelly-fish,  not 

larger  than  a  pin's  head, 
reproduced  directly  from 
eggs,  without  passing 
through  the  Hydroid 
stage.  During  its  early 
stages  of  growth  it  prob 
ably  remains  attached  to 
floating  animals,  thus 
leading  a  kind  of  para 
sitic  existence ;  but  as 
its  habits  are  not  accu 
rately  known,  this  cannot 
be  asserted  as  a  constant 
fact  respecting  them. 
The  veil  in  this  Jelly 
fish  is  very  large,  form 
ing  pendent  pouches 
hanging  from  the  cir 
cular  canal  (see  Fig. 
51),  and  leaving  but 
just  room  enough  for 
the  passage  of  the  pro 
boscis  between  the  folds. 
It  may  not  be  amiss  to 
introduce  here  a  general 
account  of  this  organ, 
which  occurs  in  many 
of  the  Medusae,  though 
it  has  very  different  pro 
portions  in  the  various  kinds.  It  is  a  delicate  membrane,  hang 
ing  from  the  circular  tube,  so  as  partially  to  close  the  mouth  of 
the  bell,  leaving  a  larger  or  smaller  opening  for  the  passage 
of  the  water,  which  is  taken  in  and  forced  out  again  by  the  alter 
nate  expansions  and  contractions  of  the  bell. 

Fig.  51.     Campanella  seen  in  profile  ;  greatly  magnified. 
Tig.  62.     Same,  seen  from  below. 


CIRCE.  45 

There  are  but  four  chymiferous  tubes  in  the  Campanella, 
and  four  stiff  tentacles,  which  in  consequence  of  the  pecu 
liar  character  of  the  veil  appear,  when  the  animal  is  seen  in 
profile,  to  start  from  the  middle  of  the  disk.  The  ovaries  con 
sist  of  eight  pouches,  placed  near  the  point  of  junction  of  the  four 
chymiferous  tubes.  (Fig.  52.)  This  little  Medusa  is  of  a  dark 
yellowish  color  with  brownish  ocellated  spots,  scattered  profusely 
over  the  upper  part  of  the  disk. 

Circe.    (TracJiynema  digitale  A.  AG.) 

Among  the  Jelly-fishes,  the  position  of  which  is  somewhat 
doubtful,  is  the  Circe  (Fig.  53),  differing  greatly  in  outline 
from  the  ordinary  Jelly-  Fig.  53. 

fishes.  As  may  be  seen 
in  Figure  53,  the  bell 
forms  but  a  small  por 
tion  of  the  animal ;  it  rises 
in  a  sharp  cone  on  the 
summit,  thinning  out  at 
the  lower  edge,  to  form 
the  large  cavity  in  which 
hangs  the  long  proboscis 
and  the  eight  ovaries,  four 
of  which  may  be  seen  in 
Fig.  53  crowded  with  eggs. 
The  Circe  differs  in  con 
sistency,  as  well  as  in  form, 
from  other  Jelly-fishes.  It 
is  hard  and  horny  to  the 
touch,  and  the  veil,  usu 
ally  so  light  and  filmy,  is 
here  a  thick  folded  membrane,  which  at  every  stroke  of  the  ani 
mal  forces  the  water  in  and  out  of  the  cavity.  It  is  very  active, 
moving  by  powerful  jerks,  each  one  of  which  throws  it  far  on  its 
way.  It  advances  usually  in  straight  lines  ;  or,  if  it  wishes  to 
change  its  direction,  it  drives  the  water  out  of  the  veil  suddenly 

Fig.  53.    Trachynema  digitale  ;  about  twice  the  natural  size. 


46 


MARINE   ANIMALS    OF    MASSACHUSETTS    BAY. 


on  one  side  or  the  other,  so  as  to  shoot  off,  sometimes  at  right 
angles  with  its  former  path.  Four  large  pedunculated  eyes,  hid 
den  in  the  figure  by  the  tentacles,  stand  out  prominently  from  the 
circular  tube.  When  the  animal  is  in  motion,  the  tentacles  are 
carried  closely  curled  around  the  edge  of  the  disk,  as  in  Fig. 
53,  where  the  Circe  is  represented  under  a  magnifying  power 
of  two  and  a  half  diameters.  This  Jelly-fish  is  of  a  delicate  rose 
color,  the  tentacles  assuming,  however,  a  dark-purple  tint  at 
their  extremities  when  contracted. 


Fig   54. 


z&mji 
4^r 

W 


i^yi  i 

fMWil  , 


Lucernaria.    (Halyclistus  auricula  CLARK.) 

One  of  the  prettiest  and  most  graceful,  as  well  as  one  of  the 
most  common  of  our  Jelly-fishes,  is  the  Lucernaria  (Fig.  54).    It 

has  such  an  extraordinary  con 
tractility  of  all  its  parts,  that  it  is 
not  easy  to  describe  it  under  any 
definite  form  or  position,  since 
both  are  constantly  changing  ; 
but  perhaps  of  all  its  various  at 
titudes  and  outlines  none  are 
more  normal  to  it  than  those 
given  in  Fig.  54.  It  frequently 
raises  itself  in  the  upright  po 
sition  represented  here  by  the 
individual  highest  on  the  stem, 
spreading  itself  in  the  form  of  a 
perfectly  symmetrical  cup  or  vase, 
the  margin  of  which  is  indented  by  a  succession  of  inverted  scal 
lops,  the  point  of  junction  between  every  two  scallops  being 
crowned  by  a  tuft  of  tentacles.  But  watch  it  for  a  while,  and 
the  sides  of  this  vase  turn  backward,  spreading  completely  open, 
till  they  present  the  whole  inner  surface,  with  the  edges  even 
curved  a  little  downward,  drooping  slightly,  and  the  proboscis 
rising  in  the  centre.  In  such  an  attitude  one  may  trace  with 
ease  the  shape  of  the  mouth,  the  lobes  surrounding  it,  as  well  as 
the  tubes  and  cavities  radiating  from  it  toward  the  margin.  A 


Fig.  54.     Group  of  Luceraariie  attached  to  eel-gra?s ;  natural  size. 


LUCERNARIA.  47 

touch  is,  however,  sufficient  to  make  it  close  upon  itself,  shrink 
ing  together  in  the  attitude  of  the  third  individual  in  Fig.  54,  or 
even  drawing  its  tentacles  completely  in,  and  contracting  all  its 
parts  till  it  looks  like  a  little  ball  hanging  on  the  stem.  These 
are  but  a  few  of  its  manifold  changes,  for  it  may  be  seen  in  every 
phase  of  expansion  and  contraction.  Let  us  now  look  for  a  mo 
ment  at  the  details  of  its  structure.  The  resemblance  to  a  cup  or 
vase,  as  in  the  upper  figure  of  the  wood-cut  (Fig.  54),  is  decep 
tive  ;  for  a  vase  is  hollow,  whereas  the  Lucernaria,  though  so  deli 
cate  and  transparent  that  its  upper  surface,  when  thus  stretched, 
seems  like  a  mere  film,  is  nevertheless  a  solid  gelatinous  mass, 
traversed  by  certain  channels,  cavities,  and  partitions,  but  other 
wise  continuous  throughout.  The  peduncle  by  which  it  is  at 
tached  is  but  an  extension  of  the  floor  of  a  gelatinous  disk,  cor 
responding  to  that  of  any  Jelly-fish.  Four  tubes  pass  through  the 
whole  length  of  this  peduncle,  and  open  into  four  chambers, 
dividing  the  digestive  cavity  above  into  as  many  equal  spaces. 
(Fig.  55.)  These  spaces  are  Fiff  55 

produced  by  folds  in  the  up 
per  floor  of  the  disk,  uniting 
it  to  the  lower  floor  at  giv 
en  distances,  and  forming  so 
many  partition-walls,  dividing 
the  digestive  sac  into  four  dis 
tinct  cavities.  These  lines  of 
juncture  between  the  two 
floors,  where  the  partitions  oc 
cur,  produce  the  four  radial 
ing  lines,  running  from  the 
proboscis  to  the  margin  of  the 
disk,  on  the  upper  surface.  (Fig.  55.)  The  triangular  figures, 
running  from  the  mouth  to  each  cluster  of  tentacles,  are  pro 
duced  by  the  ovaries,  which  consist  of  distinct  pouches  or  bags 
attached  to  the  upper  surface  of  the  disk,  and  hanging  down  into 
the  cavities  below ;  every  little  dot  within  these  triangular  spaces 
represents  such  a  bag.  Each  bag  is  crowded  with  eggs,  which 
drop  into  the  digestive  cavity  at  the  spawning  season,  and  are 

Fig  55.     Lucernaria  seen  from  the  mouth  side 


48  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

passed  out  at  the  mouth.  The  tentacles  always  grow  in  clus 
ters,  but  are  nevertheless  arranged  according  to  a  regular  order. 
They  are  club-shaped  at  their  extremities,  but  are  hollow 
throughout,  opening  into  the  chambers  of  the  digestive  cavity, 
two  of  the  clusters  thus  being  connected  with  each  chamber. 
Their  chief  office  seems  to  be  to  catch  the  food  and  convey  it  to 
the  mouth,  though  they  may  also  be  used  as  a  kind  of  suckers, 
and  the  animal  not  unfrequently  attaches  itself  by  means  of  these 
appendages.  Between  every  two  clusters  of  tentacles  will  be  ob 
served  a  short,  single  appendage,  of  an  entirely  different  appear 
ance.  These  are  the  so-called  auricles,  and  though  so  unlike 
tentacles  in  the  adult  animal,  when  in  their  earlier  stages  (Fig. 
56)  they  resemble  each  other  closely.  But  as  their  development 
goes  on,  the  tentacles  stretch  out  into  longer, 
more  delicate  flexible  organs,  while  the  auri 
cles  remain  short  and  compact  throughout 
life.  They  contain  a  slight  pigment  spot 
representing  an  eye,  though  how  far  it  serves 
the  purpose  of  vision  remains  doubtful. 
They  are  chiefly  used  by  the  animal  as  a 
means  of  adhering  to  any  surface  upon  which 
it  may  wish  to  fasten  itself;  for  the  Lucer- 
naria,  though  usually  found  attached  to  eel-grass  in  shoal  water, 
has  the  power  of  independent  motion,  and  frequently  separates 
from  its  resting-place,  floating  about  freely  in  the  water  for  a  while, 
or  attaching  itself  anew  by  means  of  the  auricles  and  tentacles 
upon  some  other  object.  The  color  of  this  pretty  Acaleph  varies 
from  a  greenish  hue  to  green,  with  a  faint  tinge  of  red,  or  to  a 
reddish  brown.  One  of  its  commonest  and  most  exquisite  tints  is 
that  of  a  pale  aqua-marine.  It  may  be  found  along  our  shores 
wherever  the  eel-grass  grows,  and  as  far  out  as  this  plant  extends. 
It  thrives  admirably  in  confinement,  and  for  this  reason  is  espe 
cially  adapted  to  the  aquarium. 

Fig.  56     Young  Lucernaria  ;  magnified 


Library 


HYDROIDS. 


HYDROIDS. 


UNDER  this  order,  the  general  character  of  which  has  already 
been  explained  in  the  introductory  chapter  on  Acalephs,  are  in 
cluded  a  number  of  groups  which,  whether  as  Hydroid  commu 
nities  in  their  earlier  phases  of  existence,  or  as  free  swimming 
Medusae  in  their  farther  development,  challenge  our  admiration, 
both  for  their  beauty  of  form  and  color,  and  their  grace  of  motion. 
Some  of  them  are  so  minute  that  they  escape  the  observation  of 
all  but  those  who  are  laboriously  seeking  for  the  hidden  treas 
ures  of  the  microscopic  world,  but  the  greater  number  are  large 
enough  to  be  readily  found  by  the  most  inexperienced  collector, 
when  his  attention  is  once  drawn  to  them  ;  and  he  may  easily 
stock  his  aquarium  with  these  pretty  little  communities,  and 
even  trace  the  development  of  the  Jelly-fishes  upon  them. 

To  the  Hydroids  belong  the  Campanularians,  the  Sertularians, 
and  the  Tubularians.  Some  examples  of  each,  as  represented  on 
our  shores,  will  be  found  under  their  different  heads,  accompa 
nied  with  full  descriptions.  There  is  another  group  usually  con 
sidered  as  distinct  from  Hydroids,  and  known  as  a  separate  order 
among  Acalephs,  under  the  name  of  Siphonophorae,  but  included 
with  them  here  in  accordance  with  the  views  of  Vogt,  Agassiz, 
and  others,  in  whose  opinion  they  differ  from  the  ordinary  Hy 
droid  communities  only  in  being  free  and  floating,  instead  of 
fixed  to  the  ground.  Some  new  facts,  published  here  for  the 
first  time,  tend  to  sustain  the  accuracy  of  this  classification.* 
With  these  few  preliminary  remarks  to  show  the  connection  of 
the  order,  let  us  now  look  at  some  of  the  animals  belonging  to  it 
more  in  detail. 

Campanularians  . 

All  the  Campanularians,  of  which  Oceania  (Fig.  68),  Clytia 
(Fig.  73),  and  Eucope  (Fig.  61)  form  a  part,  belong  among 
those  little  shrub-like  communities  of  animals  called  Hydroids, 

*  See  Chapter  on  Nanomia. 

7 


50  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

from  which  most  of  our  Jelly-fishes  are  developed.  They  differ 
in  one  essential  feature  from  the  Tubularians.  (Fig.  93.)  The 
whole  stem,  from  summit  to  base,  is  enveloped  in  a  horny  sheath, 
extending  around  both  the  fertile  and  sterile  individuals  of  the 
community,  and  forming  a  network  at  the  base  of  the  stem, 
which  serves  as  a  kind  of  foundation  for  the  whole  stock.  To 
the  naked  eye  such  a  community  looks  like  a  tiny  shrub  (see 
Fig.  57),  with  the  branches  growing  in  regular  alternation  on 
either  side  of  the  stems.  The  reproductive  calycles,  i.e.  the  pro 
tecting  envelopes  covering  the  young  Medusae,  usually  arise  in 
the  angles  of  the  branches  formed  by  a  prolongation  of  the 
sheath.  These  calycles  or  bells,  as  they  are  called,  assume  a 
great  variety  of  shapes,  —  elliptical,  round,  pear-shaped,  or  ringed 
like  the  Clytia.  (Fig.  72.)  In  one  such  bell  there  may  be  no 
less  than  twenty  or  thirty  Medusae  developed  one  below  the 
other  ;  when  ready  to  hatch,  the  calycle  bursts  and  allows  them 
to  escape. 

Eucope.    (Eucope  diapliana  AG.) 

In  Figs.   60  and  61  we  have  a  representation  of  our  little 
Eucope,  one  of  the  prettiest  of  the  Jelly-fishes  belonging  to  this 

Fig.  57.  Fig.  58. 


group  ;  Fig.  57  represents  the  Hydroid  from  which  it  arises ;  a 
single  branch  with  the  reproductive  bell  being  magnified  in  Fig. 


Fig.  57.     Hyrtrarium  of  Eucope  ;  natural  size 
Fig.  58.     Portion  of  Fig.  57  ;  magnified. 


EUCOPE. 


51 


58.  In  Fig.  59  is  seen  a  portion  of  the  Jelly-fish  disk,  with  the 
fringe  of  tentacles  highly  magnified.  The  disk  of  the  Eucope 
(Fig.  60)  looks  like  a  shallow  bell,  of  which  the  proboscis  often 
seems  to  form  the  handle  ;  for  the  disk  has  such  an  extraordi- 


Fig.  59. 


Fig.  60. 


nary  thinness  that  it  turns  inside  out  with  the  greatest  ease,  so 
that  the  inner  surface  may  become  at  any  moment  the  outer  one, 
with  the  proboscis  projecting  from  it,  as  in  Fig.  60,  while  the  next 
movement  of  the  animal  may  reverse  its  whole  position,  and  the 
proboscis  then  hangs  down  from  the  inside,  as  in  other  Jelly- 
fishes.  (See  Fig.  61.) 

The  tentacles  are  solid  and  stiff  like  little  hairs,  and  two  of 
them,  in  each  quarter-segment  of  the  disk,  have  small  concretions 

Fig.  61  Fig.  62. 


at  the  base,  which  are  no  doubt  eye-specks.  (See  Fig.  62.) 
Along  the  chymiferous  tubes  little  swellings  are  developed,  which 
increase  gradually,  and  become  either  ovaries  or  spermaries, 
according  to  the  sex  of  the  animal.  (Fig.  63.)  In  the  adult  the 
genital  organs  hang  down,  like  elongated  bags,  from  the  chy- 

Fig.  59.     Part  of  marginal  tube  and  tentacles  of  Eucope,  greatly  magnified  ;  e  eye-speck,  b  base  of 
tentacle,  r  reentering  base  of  tentacle. 
Fig.  60.    Young  Eucope  ;  magnified. 
Fig.  61.    Adult  Eucope  seen  in  profile  ;  magnified. 
Fig.  62.     Quarter  disk  of  Fig  60,  seen  from  below  ;  e  e  tentacles  bearing  eye-speck. 


52  MARINE    ANIMALS    OF   MASSACHUSETTS    BAY. 

miferous  tubes.  (Fig.  64.)  The  tentacles  are  numerous,  multi 
plying  to  about  a  hundred  and  ninety-two  in  the  adult,  and  in 
creasing  according  to  the  numerical  law  to  be  explained  in  the 
description  of  the  Oceania. 

This  little  Jelly-fish  is  one  of  the  most  common  in  our  Bay. 

Fig.  63.  Fig.  64. 


There  is  not  a  night  or  day  when  they  cannot  be  taken  in  large 
numbers,  from  the  early  spring  till  late  in  the  autumn  ;  and  as 
the  breeding  season  lasts  during  the  whole  of  that  period,  they 
are  found  in  all  possible  stages  of  growth.  In  consequence  of 
this,  the  course  of  their  development,  and  the  relation  between 
the  different  prises  of  their  existence  as  Hydroids,  and  afterwards 
as  Acalephs,  are  well  known,  though  the  successive  steps  of  their 
growth  have  not  been  traced  connectedly,  as  in  some  of  the  other 
Jelly-fishes,  the  Tima  or  Melicertum,  for  instance.  The  process 
is,  however,  so  similar  throughout  the  class  of  Hydroids,  that, 
having  followed  it  from  beginning  to  end  in  some  of  the  groups, 
we  have  the  key  to  the  history  of  others,  whose  development  has 
not  been  so  fully  traced.  The  eggs  laid  by  the  Eucope  in  the 
autumn  develop  into  planula3,  which  acquire  their  full  size  as 
Hydroid  communities  toward  the  close  of  the  winter,  and  the 
development  of  the  young  Medusae  upon  them,  as  described 
above,  begins  with  the  opening  spring. 

Fig.  63.    Quarter-disk  of  young  Eucope,  older  than  Fig.  62,  with  a  second  set  of  tentacles  (2)  be 
tween  the  first  set  (1). 
Fig.  64.    Magnified  quarter-disk  of  adult  Eucope. 


OCEANIA.  53 

Oceania.     (Oceania  languida  A.  AG.) 

The  Oceania  (Fig.  68)  is  so  delicate  and  unsubstantial,  that 
with  the  naked  eye  one  perceives  it  only  by  the  more  prominent 
outlines  of  its  structure.  "We  may  see  the  outline  of  the  disk,  but 
not  the  disk  itself ;  we  may  trace  the  four  faint  thread-like  lines 
produced  by  the  radiating  tubes  traversing  the  disk  from  the 
summit  to  the  margin  ;  and  we  may  perceive,  with  far  more  dis 
tinctness,  the  four  ovaries  attached  to  these  tubes  near  their  base  ; 
we  may  see  also  the  circular  tube  uniting  the  radiating  tubes, 
and  the  tentacles  hanging  from  it,  and  we  can  detect  the  edge  of 
the  filmy  veil  that  fringes  the  margin  of  the  disk.  But  the  sub 
stance  connecting  all  these  organs  is  not  to  be  distinguished  from 
the  element  in  which  it  floats,  and  the  whole  structure  looks  like 
a  slight  web  of  threads  in  the  water,  without  our  being  able  to 
discern  by  what  means  they  are  held  together.  Under  the  mi 
croscope,  however,  the  invisible  presently  becomes  visible,  and  we 
find  that  this  Jelly-fish,  like  all  others,  has  a  solid  gelatinous 
disk. 

Let  us  begin  with  its  earlier  condition.  When  it  first  escapes 
from  the  parent  Hydroid  stock,  the  Oceania  is  almost  spherical 
in  form.  (See  Fig.  65.)  The  disk  is  divided  by  four  chymiferous 
tubes,  running  from  the  summit  to  the  margin,  where  they  meet 
the  circular  tube  in  which  they  all  unite.  At  this  time,  it  has 
but  two  well-developed  tentacles,  opposite  each  other  on  the  mar- 
Fig.  65. 


gin  of  the  disk,  just  at  the  base  of  two  of  the  chymiferous  tubes 
(Fig.  66),  while  two  others  are  just  discernible  in  a  rudimentary 

Fig.  65.     Young  Oceania  just  escaped  from  its  reproductive  calycle  ;  magnified. 
Fig.  66.    The  same  as  Fig.  65,  from  below,  still  more  magnified  ;  t  long  tentacles,  t '  rudimentary  ten 
tacle,  e  eye-speck  on  each  side  of  base  of  tentacles. 


54  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

state,  forming  slight  projections  at  tlie  base  of  the  two  other 
tubes.  Fig.  66  gives  a  view  of  the  animal  from  below,  at  this 
stage  of  its  growth,  while  Fig.  65  shows  it  in  profile.  It  will  be 
seen  by  the  latter  how  very  spherical  is  the  outline  of  the  disk  at 
this  period,  while  the  proboscis,  in  which  are  placed  the  mouth 
and  digestive  cavity,  is  quite  long,  and  hangs  down  considerably 
below  the  lower  surface  of  the  disk.  As  the  animal  advances  in 
age  the  disk  loses  its  spherical  outline,  and  becomes  much  flat 
tened,  as  may  be  seen  in  Fig.  67.  It  may  be  well  to  introduce 

here  some  explanation  of  the  law  ac- 

Fig.  67.  r 

cording  to  which  the  different  sets  of 
tentacles  follow  each  other  in  succes 
sive  cycles  of  growth,  since  it  is  a  law 
of  almost  universal  application  in  Jelly- 
fishes  and  Polyps ;  and,  owing  to  the 
smaller  number  and  simpler  arrange 
ment  of  the  tentacles  in  Oceania,  it  may  be  more  easily  analyzed 
in  them  than  in  many  others,  where  the  number  and  complication 
of  the  different  sets  of  tentacles  make  it  very  difficult  to  trace 

their  relation  to 
each  other  dur 
ing  their  successive 
growth.  We  have 
seen  that  the  Oce 
ania  begins  life 
with  only  two  ten 
tacles.  These  form 
the  first  set,  and 
are  marked  with 
the  number  1  in 
the  subjoined  dia 
gram,  which  gives 
the  plan  of  all  the 
different  sets  in 
their  regular  order.  The  second  set,  marked  2,  consists  also  of 
two,  which  are  developed  at  equal  distances  between  the  first  two, 
i.  e.  at  right  angles  with  them.  The  third  set,  however,  marked  3, 

Fig.  67.    Young  Oceania,  older  than  Fig.  65  ;  magnified. 


OCEANIA.  55 

consists  of  four,  as  do  all  the  succeeding  sets,  and  they  are  de 
veloped  between  the  first  and  second.  The  fourth  set  comes  in  be 
tween  the  first  and  third  ;  the  fifth  between  the  third  and  second  ; 
the  sixth  between  the  first  and  fourth  ;  the  seventh  between  the 
fifth  and  second  ;  the  eighth  between  the  third  and  fourth  ;  the 
ninth  between  the  fifth  and  third.  The  ultimate  number  of  ten 
tacles  in  the  Oceania  is  thirty-two,  or  sometimes  thirty-six,  and  the 
cycles  always  in  twos  or  multiples  of  two.  But  whatever  be  the 
number  included  in  the  successive  sets  of  tentacles,  and  the 
unit  for  the  first  set  ranges  from  two  to  forty-eight,  the  law  in 
different  kinds  of  Jelly-fishes  is  always  the  same,  the  youngest 
set  always  forming  between  the  oldest  preceding  set.  Thus  the 
fourth  set  comes  in  between  the  first  and  third,  and  the  fifth  be 
tween  the  second  and  third,  the  intervals  occupied  now  by  the 
fourth  set,  being  limited  by  the  first  set  of  tentacles  011  one  side, 
and  by  the  third  set  on  the  other  side,  while  the  intervals  occu 
pied  by  the  fifth  set  are  bounded  by  the  second  and  third  sets. 

The  little  spheres  represented  be 
tween  the  tentacles  on  the  mar 
gin  of  the  disk,  in  Figs.  65-67, 
are  eye-specks,  and  these  continue 
to  increase  in  number  with  age  ; 
in  this  the  Oceania  differs  from 
the  Eucope,  in  which  it  will  be 
remembered  there  were  but  two 
eye-specks  in  each  quarter-seg 
ment  of  the  disk  throughout 
life.  Fig.  68  represents  the  adult 
Oceania  in  full  size,  when  it  aver 
ages  from  an  inch  and  a  half  to  two 
inches  in  diameter.  It  is  slow  and  languid  in  its  movements, 
coming  to  the  surface  only  in  the  hottest  hours  of  the  sum 
mer  days  ;  at  such  times  it  basks  in  the  sun,  turning  lazily 
about,  and  dragging  its  tentacles  after  it  with  seeming  effort. 
Sometimes  it  remains  for  hours  suspended  in  the  water,  not 
moving  even  its  tentacles,  and  offering  a  striking  contrast  to 
its  former  great  activity  when  young,  and  to  the  lively  little 

Fig.  68.    Adult  Oceania ;  natural  size. 


56  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

Eucope,  which  darts  through  the  water  at  full  speed,  hardly  stop 
ping  to  rest  for  a  moment.  If  the  Oceania  be  disturbed  it  flattens 
its  disk,  and  folds  itself  up  somewhat  in  the  shape  of  a  bale  (see 
Fig.  69),  remaining  perfectly  still,  with  the  tentacles  stretching 
in  every  direction.  When  the  cause  of  alarm  is  removed,  it 

gently  expands  again,  re 
suming  its  natural  outline 
and  indolent  attitudes.  The 
number  of  these  animals  is 
amazing.  At  certain  sea 
sons,  when  the  weather  is 
favorable,  the  surface  of  the 
sea  may  be  covered  with 
them,  for  several  miles,  so 
thickly  that  their  disks 
touch  each  other.  Thus  they  remain  packed  together  in  a  dense 
mass,  allowing  themselves  to  be  gently  drifted  along  by  the 
tide  till  the  sun  loses  its  intensity,  when  they  retire  to  deeper 
waters.  Some  points,  not  yet  observed,  are  still  wanting  to  com 
plete  the  history  of  this  Jelly-fish.  By  comparing  such  facts, 
however,  as  are  already  collected  respecting  it,  with  our  fuller 
knowledge  of  the  same  process  of  growth  in  the  Eucope,  Tima, 
and  Melicertum,  we  may  form  a  tolerably  correct  idea  of  its  de 
velopment.  It  is  hatched  from  a  Campanularia. 

Clytia.    (Clytia  bicophora  AG.) 

In  Figs.  70-73  we  have  the  Acalephian  and  Hydroid  stages 
of  the  Clytia  (Fig.  73),  another  very  pretty  little  Jelly-fish,  closely 
allied  to  the  Oceania.  When  first  hatched,  like  the  Oceania,  it  is 
very  convex,  almost  thimble-shaped  (see  Fig.  70),  but  a  little 
later  the  disk  flattens  and  becomes  more  open,  as  in  Fig.  71.  In 
Fig.  72,  we  have  a  branch  of  the  Hydroid,  a  Campanularia, 
greatly  magnified,  with  the  annulated  reproductive  calycle  at 
tached  to  it,  and  crowded  with  Jelly-fishes  ready  to  make  their 
escape  as  soon  as  the  calycle  bursts.  The  adult  Clytia  (Fig.  73) ' 
is  somewhat  smaller  and  more  active  than  the  Oceania,  and 

Fig.  69.     Attitude  assumed  by  Oceania  when  disturbed. 


CLYTIA. 


57 


is  easily  recognized  by  the  black  base  of  its  tentacles,  at  their 
point  of  juncture  with  the  margin  of  the  disk.     It  is  more  corn- 
Fig-  70.  Fig.  71. 


monly  found  at  night,  than  in  the  day-time,  being  nocturnal  in 
its  habits. 

Fig.  72.  Fig.  73. 


Zygodactyla.    (Zygodactyla  groenlandica  AG.) 

Little  has  been  known,  and  still  less  published,  of  this  remark 
able  genus  of  Jelly-fish  (Figs.  74,  75)  up  to  the  present  time. 
The  name  Zygodactyla,  or  Twinfinger,  was  given  to  it  by  Brandt, 
from  drawings  made  by  Mertens,  who  had  some  opportunity  of 
studying  it  in  his  journey  around  the  world.  These  drawings 

Fig.  70.    Young  Clytia  just  escaped  from  the  reproductive  calycle. 
Fig.  71.     Clytia  somewhat  older  than  Fig.  70. 
Fig.  72      Magnified  portion  of  Hydrarium  of  Clytia. 
Fig.  73.     Adult  Clytia  ;  twice  natural  size. 
8 


58  MARINE   ANIMALS    OF   MASSACHUSETTS   BAY. 

were  published  in  the  Transactions  of  the  St.  Petersburg  Academy. 
In  the  year  1848  Professor  Agassiz  read  a  paper  upon  one  of  the 
species  of  this  genus  belonging  to  our  coast,  before  the  American 
Academy,  in  which  he  called  it  Rhacostoma,  not  being  aware 
that  it  had  already  received  a  name,  and  gave  some  account  of 
its  extraordinary  phosphorescent  properties.  The  name  Rhacos 
toma  must  of  course  yield  to  that  of  Zygodactyla,  which  has  a 
prior  claim. 

The  average  size  of  this  Jelly-fish  when  full  grown  is  from 
seven  to  eight  inches  in  diameter ;  sometimes  it  may  measure 

Fig.  74. 


even  ten  or  eleven,  but  this  is  rather  rare.  The  light-violet  col 
ored  disk  is  exceedingly  delicate  and  transparent,  its  edge  being 
fringed  with  long  fibrous  tentacles,  tinged  with  darker  violet  at 
their  point  of  juncture  with  the  disk,  and  hanging  down  a  yard 
and  more  when  fully  extended,  though  they  vary  in  length  ac 
cording  to  the  size  of  the  specimen,  and,  in  consequence  of  their 
contractile  power,  may  seem  much  shorter  at  some  moments  than 
at  others.  The  radiating  tubes  in  this  Jelly-fish  are  exceedingly 

Fig.  74.    Zygodactyla  seen  from  above. 


ZYGODACTYLA.  59 

numerous,  the  whole  inner  surface  of  the  disk  being  ribbed  with 
them.  (See  Figs.  74  and  75.)  The  ovaries  follow  the  length  of 
the  tubes,  though  they  do  not  extend  quite  to  their  extremity, 
where  they  join  the  circular  tube  around  the  margin  of  the  disk  ; 
nor  do  they  start  exactly  at  the  point  where  the  tubes  diverge 
from  the  central  cavity,  but  a  little  below  it.  (Fig.  74.)  Each 
ovary  consists  of  a  long,  brownish,  flat  bag,  split  along  the  mid 
dle,  so  closely  folded  together  that  it  seems  like  a  flat  blade 
attached  along  the  length  of  the  tube.  Perhaps  a  better  compar 
ison  would  be  to  a  pea-pod  greatly  elongated,  with  the  edges  split 
along  their  line  of  juncture,  and  attached  to  a  tube  of  the  same 
length.  The  ovaries  are  not  perfectly  straight,  but  slightly  wav 
ing,  as  may  be  seen  in  Fig.  74,  and  these  undulations  are  stronger 
when  the  ovaries  are  crowded  with  eggs,  as  is  the  case  at  the 
time  of  spawning. 

The  large  digestive  cavity  hangs  from  the  centre  of  the  under 
side  of  the  disk  (Fig.  75),  terminating  in  the  proboscis,  which,  in 

Fig.  75. 


this  kind  of  Jelly-fish,  is  short  in  proportion  to  the  diameter  of 
the  disk,  while  the  opening  of  the  mouth  is  very  large.  (Fig.  74.) 
It  is  unfortunate  that  a  variety  of  inappropriate  names,  likely  to 
mislead  rather  than  aid  the  unscientific  observer,  have  been  ap 
plied  to  different  parts  of  the  Jelly-fish.  What  we  call  here  di 
gestive  cavity,  proboscis,  and  mouth,  are,  in  fact,  parts  of  one 
organ.  An  exceedingly  delicate,  transparent,  filmy  membrane 
hangs  from  the  under  side  of  the  disk ;  that  membrane  forms  the 
outer  wall  of  the  digestive  cavity,  which  it  encloses  ;  it  narrows 

Fig.  75.    Zygodactyla  seen  in  profile. 


60  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

toward  its  lower  margin,  leaving  open  the  circular  aperture  called 
the  mouth  ;  this  narrowing  of  the  membrane  is  produced  by  a 
number  of  folds  in  its  lower  part,  while  at  its  margin  these  folds 
spread  out  to  form  ruffles  around  the  edge  of  the  mouth,  and 
these  ruffles  again  extend  into  the  long  scalloped  fringes  hanging 
down  below. 

The  motion  of  these  Jelly-fishes  is  very  slow  and  sluggish. 
Like  all  their  kind,  they  move  by  the  alternate  dilatation  and 
contraction  of  the  disk,  but  in  the  Zygodactyla  these 'undulations 
have  a  certain  graceful  indolence,  very  unlike  the  more  rapid 
movements  of  many  of  the-  Medusae.  It  often  remains  quite  mo 
tionless  for  a  long  time,  and  then,  if  you  try  to  excite  it  by  dis 
turbing  the  water  in  the  tank,  or  by  touching  it,  it  heaves  a  slow, 
lazy  sigh,  with  the  whole  body  rising  slightly  as  it  does  so,  and 
then  relapses  into  its  former  inactivity.  Indeed,  one  cannot  help 
being  reminded,  when  watching  the  variety  in  the  motions  of  the 
different  kinds  of  Jelly-fishes,  of  the  difference  of  temperament  in 
human  beings.  There  are  the  alert  and  active  ones,  ever  on  the 
watch,  ready  to  seize  the  opportunity  as  it  comes,  but  missing  it 
sometimes  from  too  great  impatience  ;  and  the  slow,  steady  peo 
ple,  with  very  regular  movements,  not  so  quick  perhaps,  but  as 
successful  in  the  long  run  ;  and  the  dreamy,  indolent  characters, 
of  which  the  Zygodactyla  is  one,  always  floating  languidly  about, 
and  rarely  surprised  into  any  sudden  or  abrupt  expression.  One 
would  say,  too,  that  they  have  their  aristocratic  circles ;  for  there 
is  a  delicate,  high-bred  grace  about  some  of  them  quite  wanting 
in  the  coarser  kinds.  The  lithe,  flexible  form  of  the  greyhound 
is  not  in  stronger  contrast  to  the  heavy,  square  build  of  the  bull 
dog,  than  are  some  of  the  lighter,  more  frail  species  of  Jelly-fish 
to  the  more  solid  and  clumsy  ones.  Among  these  finer  kinds  we 
would  place  the  Tima.  (Fig.  76.) 

Tima.    (Tima  formosa  AG.) 

One's  vocabulary  is  soon  exhausted  in  describing  the  dif 
ferent  degrees  of  consistency  in  the  substance  of  Jelly-fishes. 
Delicate  and  transparent  as  is  the  Tima,  it  has  yet  a  certain 
robustness  and  solidity  beside  the  Oceania,  described  above.  In 


TIMA. 


61 


fact,  all  are  gelatinous,  all  are  more  or  less  transparent,  and  it  is 
not  easy  to  describe  the  various  shades  of  solidity  in  jelly.  Per 
haps  they  may  be  more  accurately  represented  by  the  impression 
made  upon  the  touch  than  upon  the  sight.  If,  for  instance,  you 
place  your  hand  upon  a  Zygodactyla,  you  feel  that  you  have 
come  in  contact  with  a  substance  that  has  a  positive  consistency  ; 
but  if  you  dip  your  finger  into  a  bowl  where  a  Tima  is  swimming, 
and  touch  its  disk,  you  will  feel  no  difference  between  it  and  the 

Fig.  76. 


Library 


California- 


in  which  it  floats,  and  will  not  be  aware  that  you  have 
reached  it  till  the  animal  shrinks  away  from  the  contact. 

The  adult  Tima,  represented  in  Fig.  76,  is  not  more  than  an 
inch  and  a  half  or  two  inches  in  diameter.  Instead  of  count 
less  tubes  diverging  from  the  digestive  cavity  to  the  margin  of 
the  disk,  as  in  the  Zygodactyla,  there  are  but  four.  The  di 
gestive  cavity  in  the  Tima  is  much  smaller  than  in  the  Zygo 
dactyla,  and  is  placed  at  the  end  of  the  proboscis,  which  is  long, 
and  hangs  down  far  below  the  disk.  This  removal  of  the  diges 
tive  cavity  to  the  extremity  of  the  proboscis  gives  to  the  tubes 

Fig.  76.    Tima;  half  natural  size. 

Fig.  77.    One  of  the  lips  of  the  mouth  at  the  extremity  of  the  long  proboscis  5  m  mouth,  d  digestive 
cavity,  c  chymiferous  tube. 


62  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

arising  from  it  a  very  different  and  much  sharper  curve  than 
they  have  in  the  Zygodactyla.  In  the  Tima  they  start  from  the 
end  of  the  proboscis,  as  may  be  seen  in  the  wood-cut  (Fig.  76), 
and  then  turn  abruptly  off,  when  they  arrive  at  the  under  surface 
of  the  disk,  to  reach  its  margin.  The  disk  has,  as  usual,  its  veil 
and  its  fringe  of  tentacles  ;  the  tentacles  in  the  full-grown  Tima 
are  few,  —  seven  in  all  the  four  intermediate  spaces  between  the 
tubes,  with  one  at  the  base  of  each  tube,  making  thirty-two  in 
all.  The  ovaries,  which  are  milk-white,  follow  the  line  of  the 
tubes,  as  in  the  Zygodactyla,  and  have  very  undulating  folds 
when  full  of  eggs.  The  tubes  meet  in  the  digestive  cavity, 
Fig<78.  the  margin  of  which 

spreads  out  to  form 
four  ruffled  edges  that 
hang  down  from  it. 
One  of  these  ruffles, 
considerably  magni 
fied,  is  represented 
in  Fig.  77.  In  Fig. 
78  we  have  a  portion 
of  the  Hydroid  stock 
from  which  this  Jelly 
fish  arises,  also  great 
ly  magnified.  The 
Tima  is  very  active, 
yet  not  abrupt  in  its 
motions  ;  but  when  in  good  condition  it  is  constantly  moving 
about,  rising  to  the  surface  by  the  regular  pulsations  of  the  disk, 
or  swimming  from  side  to  side,  or  poising  itself  quietly  in  the 
water,  giving  now  and  then  a  gentle  undulation  to  keep  itself  in 
position. 

Though  not  a  very  frequent  visitor  of  our  shores,  the  appear 
ance  of  the  Tima  is  not  limited  by  the  seasons,  since  they  are 
found  at  all  times  of  the  year.  It  is  a  fact,  unexplained  as  yet, 
that  the  Tima  and  many  other  Jelly-fishes  are  never  seen  except 
when  full  grown.  What  may  be  the  haunts  and  habits  of  these 
animals  from  the  time  of  their  hatching  till  they  make  their 

Fig.  78.    Magnified  head  of  Hydrarium  of  Tima. 


MELICERTUM.  63 

appearance  again  in  the  adult  condition,  is  not  known,  though  it 
is  probable  that  they  remain  at  the  bottom  during  this  period, 
and  only  come  to  the  surface  to  spawn.  This  impression  is  con 
firmed  by  the  observations  made  upon  a  very  young  Cyanea 
which  was  kept  for  a  long  time  in  confinement ;  but  a  question 
of  this  kind  cannot  of  course  be  settled  by  a  single  experiment.* 

Melicertum.    (Melicertum  campanula  PER.  et  LES.) 

A  pretty  Medusa,  smaller  and  far  more  readily  obtained  than 
the  Tima,  is  the  Melicertum.  (Fig.  80.)  Its  disk  has  a  yellow 
ish  hue,  and  from  its  margin  hangs  a  heavy  row  of  yellow  tenta 
cles,  while  the  eight  ovaries  (Fig.  79)  are  of  a  darker  shade  of 
the  same  color.  This  little  gold 
en-tinted  Jelly-fish,  moving  through 
the  water  with  short,  quick  throbs, 
produced  by  the  rapid  rise  and  fall 
of  the  disk,  is  a  very  graceful  ob 
ject.  Its  bright  color,  made  partic 
ularly  prominent  by  the  darker  un 
dulating  lines  of  the  ovaries,  which 
become  very  marked  near  the  spawn 
ing  season,  renders  it  more  conspic 
uous  in  the  water  than  one  would 
suppose  from  its  size  ;  for  it  does  not  measure  more  than  an 
inch  in  height  when  full  grown.  (See  Fig.  80.) 

*  Since  the  above  was  written,  I  have  had  an  opportunity  of  learning  some  ad 
ditional  facts  respecting  the  habits  of  the  young  Cyanea,  which  may,  perhaps,  apply 
to  other  Jelly-fishes  also.  Having  occasion  to  visit  the  wharves  at  Provincetown  at 
about  four  o'clock  one  morning,  I  was  surprised  to  find  thousands  of  the  spring  brood 
of  Cyanese,  hitherto  supposed  to  pass  the  early  period  of  their  existence  wholly  in 
deep  water,  floating  about  near  the  surface.  They  varied  in  size,  some  being  no 
larger  than  a  three-cent-piece,  while  others  were  from  an  inch  in  diameter  to  three 
inches.  It  would  seem  that  they  make  their  appearance  only  during  the  earliest 
morning  hours,  for  at  seven  o'clock,  when  I  returned  to  the  same  spot,  they  had  all 
vanished.  It  may  be  that  other  young  Medusce  have  the  same  habits  of  early  rising, 
and  that  instead  of  coming  to  bask  in  the  midday  sunshine,  like  their  elders,  they 
prefer  the  cooler  hours  of  the  dawn.  (A  Ayassiz.} 

Fig.  79.    Melicertum  campanula  seen  from  above  ;  m  mouth,  o  o  ovaries,  1 1  tentncleg.    (Ajasniz.) 


64  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

Development  of  Melicertum  and  Tima. 

In  the  Melicertum  and  Tima  we  have  had  the  good  fortune  to 
trace  the  process  by  which  the  eggs  are  changed  into  Hydroid 
communities.  If  any  one  has  a  curiosity  to  follow  for  themselves 
this  singular  history  of  alternate  generations,  the  Melicertum  is  a 
good  subject  for  the  experiment,  as  it  thrives  well  in  confinement. 

Fig.  80. 


After  keeping  a  number  of  them  in  a  large  glass  jar  for  a  couple 
of  days  at  the  time  of  spawning,  it  will  be  found  that  the  ovaries, 
which  were  at  first  quite  full  of  eggs,  are  emptied,  and  that  a  num 
ber  of  planulae  are  swimming  about  near  the  bottom  of  the  vessel. 
After  a  day  or  two  the  outline  of  these  planulse,  spherical  at  first, 
becomes  pear-shaped  (see  Fig.  81),  and  presently  they  attach 
themselves  by  the  blunt  end  to  the  bottom  of  the  jar.  (Fig.  82.) 
Thus  their  Hydroid  life  begins  ;  they  elongate  gradually,  the 
horny  sheath  is  formed  around  them,  tentacles  arise  on  the  upper 

Fig.  80.     Melicertum  seen  in  profile  ;  natural  size. 


LAOMEDEA.  65 

end,  short  and  stunted  at  first,  but  tapering  rapidly  out  into  fine 
flexible  feelers,  the  stem  branches,  and  we  have  a  little  Hydroid 
community  (Fig.  83),  upon  which,  in  the  course  of  the  following 
spring,  the  reproductive  calycles  containing  the  Medusa  buds  will 

Fig.  83. 


Fig.  82. 


be  developed,  as  in  the  case  of  the  Eucope  and  Clytia.  The 
Tima  passes  through  exactly  the  same  process,  though  the  shape 
of  the  planula3  and  the  appearance  of  the  young  differ  from  that 
of  the  Melicertum,  as  may  be  seen  in  Fig.  78,  where  a  single 
head  of  the  Tima  Hydroid,  greatly  magnified,  is  represented. 
By  combining  the  above  observations  upon  the  development  of 
the  Hydroids  of  the  Melicertum  and  Tima  with  those  previously 
mentioned  upon  the  young  Medusa  arising  from  reproductive 
calycles  in  the  Eucope  and  Clytia,  we  get  a  complete  picture  of 
all  the  changes  through  which  any  one  of  these  Hydroid  Medusas 
passes,  from  its  Hydroid  condition  to  the  moment  when  it  enters 
upon  an  independent  existence  as  a  free  Jelly-fish. 

(Laomedea  amphora  AG.) 

The  Medusae  of  the  Campanularians  are  not  all  free.  On  the 
contrary,  in  many  of  the  species  they  always  remain  attached  to 
the  Hydroid,  never  attaining  so  high  a  development  as  the  free 
Medusae,  and  withering  on  the  stem  after  having  laid  their  eggs. 

Fig.  81.     Planula  of  Melicertum  ;  magnified. 
Fig.  82.     Cluster  of  planulse  just  attached  to  the  ground. 
Fig.  83.     Young  Hydrarium  developed  froia  planulaj  ;  magnified. 
9 


66 


MARINE   ANIMALS    OF    MASSACHUSETTS    BAY. 


Such  is  the  Laomedea  amphora,  quite  common  on  all  the  bridges 
connecting  Boston  with  the  country,  where,  on  account  of  the 
large  amount  of  food  brought  down  from  the  sewers  by  the  river, 
they  thrive  wonderfully,  growing  to  a  great  size,  sometimes  meas 
uring  from  a  foot  to  eighteen  inches  in  height. 


Sertularians. 

The  Sertularians  form  another  group  of  Hydroids  closely 
allied  to  the  Campanularians,  though  differing  from  them  in  the 
arrangement  of  the  sterile  Hydras  upon  the  stem.  Among  these 
one  of  the  most  numerous  is  the  Dynamena  {Dynamena  pumila 
Lamx.,  Fig.  84),  which  hangs  its  yellowish  fringes  from  almost 
every  sea-weed  above  low-water-mark.  It  is  especially  thick  and 
luxuriant  on  the  fronds  of  our  common  Fucus  vesiculosus.  The 
color  is  usually  of  a  pale  yellow,  though  sometimes  it  is  nearly 
white,  and  when  first  taken  from  the  water  it  has  a  glittering 
look,  such  as  a  white  frost  leaves  on  a  spray  of  grass.  Fig.  84 

Fig.  85. 


represents  such  a  cluster  in  natural  size,  while  Fig.  85  shows  a 
piece  of  the  stem  highly  magnified,  with  a  reproductive  calycle 
attached  to  the  side  of  a  sterile  Hydra  stem.  Many  of  these 
Sertularian  Hydroids  assume  the  most  graceful  forms,  hanging 
like  long  pendent  streamers  from  the  Laminaria,  or  in  other 
instances  resembling  miniature  trees.  One  of  these  tree-like 

Fig.  84.     Colony  of  Dynamena  pumila  ;  natural  size. 
Fig.  85.    Magnified  portion  of  Fig.  84. 


TUBULARIANS.  67 

Sertularians  (JDyphasia,  rosacea  Ag.),  abundant  on  all  rocks  in 
sheltered  places  immediately  below  low-water-mark,  is  repre 
sented  in  Fig.  86.  In  both  these  Sertularians  the  Medusae  wither 
011  the  stock,  never  becoming  free.  The  free  Medusae  of  the 


Fig.  86.  Fig.  87. 


Sertularians  are  only  known  in  their  adult  condition  in  a  single 
genus,  which  is  closely  allied  to  Melicertum,  and  which  is  pro 
duced  from  a  Hydroid  genus  called  Lafoea.  Fig.  87  repre 
sents  one  of  these  young  Sertularian  Medusae  (Lafoea  cornuta 
Lainx.). 

Tubularians. 

In  the  Sertularian  and  Campanularian  Hydroids  we  have  found 
that  the  communities  consist  generally  of  a  large  number  of  small 
individuals,  so  small,  indeed,  that  it  is  hardly  possible  at  first 
glance  to  distinguish  the  separate  members  of  these  miniature 
societies.  Among  the  Tubularians,  on  the  contrary,  the  commu 
nities  are  usually  composed  of  a  small  number  of  comparatively 
large  individuals  ;  and  indeed  these  Hydroids  may  even  grow 
singly,  as  in  the  case  of  the  Hybocodon  (Fig.  104),  which  attains 
several  inches  in  height.  There  is  also  another  general  feature 
in  which  the  Tubularians  differ  from  both  the  other  groups  of 
Hydroids.  In  the  latter,  the  horny  sheath  which  encloses  the 
stem  extends  to  form  a  protecting  calycle  around  the  Hydra 

Fig.  86.    Dyphasia  rosacea,  natural  size. 
Fig.  87.    Medusa  of  Lafaea. 


68 


MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 


heads.  This  protecting  calycle  is  wanting  round  the  heads 
of  the  Tubularians,  though  their  stems  are  surrounded  by  a 
sheath. 


Sarsia.  (Coryne  mirabilix  AG.) 

Among  the  most  common  of  our  Tubularians  is  a  small,  mossy 
Hydroid  (Fig.  88),  covering  the  rocks  between  tides,  in  patches 
of  several  feet  in  diameter.  Fig.  89  represents  a  single  head 
from  this  little  mossy  tuft  greatly  magnified,  in  which  is  seen  the 
medusa  bud  arising  from  the  stem  by  the  process  already  de 
scribed  in-  the  other  Hydroids.  In  Fig.  90  we  have  the  little 


Fig.  88. 


Fig.  00. 


Jelly-fish  in  its  adult  condition,  about  the  size  of  a  small  walnut, 
with  a  wide  circular  opening,  through  which  passes  the  long  pro- 
Fig.  88.    Colony  of  Coryne  ;  natural  size.  (Agassix.) 

Fig.  89.     Magnified  head  of  Coryne  5  a  stem,  t  tentacles,  o  mouth,  v  body,  d  Medusa.    (Agassiz.) 
Fig.  90.    Free  Medusa  of  Coryne.   (Ayassiz.) 


SARSIA.  69 

boscis,  hanging  from  the  under  surface  of  the  disk  to  a  consider 
able  distance  below  its  margin.  The  four  tentacles  are  of  an 
immense  length  when  compared  to  the  size  of  the  animal.  As  a 
general  thing,  the  tentacles  are  less  numerous  in  the  Tubularian 
Medusa3  than  in  those  arising  from  other  Hydroids  ;  they  want 
also  the  singular  limestone  concretions  found  at  the  base  of  the 
tentacles  in  the  Campanularian  Medu 
sae.  In  Fig.  91  we  have  one  of  the 
Tubularian  Medusas  (Turrit  vesicaria 
A.  Ag.)  which  has  a  rather  larger 
number  of  tentacles  than  is  usual 
among  these  Jelly-fishes.  We  never 
find  the  tentacles  multiplying  almost 
indefinitely  in  them,  as  in  Zygodac- 
tyla  and  Eucope.  The  little  Jelly-fish 
described  above  is  known  as  Sarsia, 
while  its  Hydroid  is  called  Coryne. 
These  names  having  been  given  to 
the  separate  phases  of  its  existence 
before  their  connection  was  understood, 
and  when  they  were  supposed  to  rep 
resent  two  distinct  animals.  They  are 
especially  interesting  with  reference 
to  the  history  of  Hydroids  in  general, 
because  they  were  among  the  first  of  these  animals  in  whom 
the  true  relation  between  the  different  phases  of  their  exist 
ence  was  discovered.  Lesson  named  the  Sarsia  after  the  great 
Norwegian  naturalist,  Sars,  to  whom  we  owe  so  large  a  part  of 
what  is  at  present  known  respecting  this  curious  subject  of  alter 
nate  generations. 


JBougainvillia.    (BougawviUia  superciliaris  AG.) 

The  Bougainvillia  (Fig.  92),  is  one  of  our  most  common 
Jelly-fishes,  frequenting  our  wharves  as  well  as  our  sea-shore 
during  the  spring.  The  tentacles  are  arranged  in  four  bunches 

Fig.  91.    Turris  vesicaria  ;  natural  size. 


70 


MARINE   ANIMALS    OF   MASSACHUSETTS   BAY. 


or  clusters  at  the  junction  of  the  radiating  tubes  with  the  cir 
cular  tube,  from  which  they  may  be  seen  extending  in  every 


Fig.  92. 


direction  whenever  these  animals  re 
main  quietly  suspended  in  the  water, 
—  a  favorite  attitude  with  them,  and 
one  which  they  retain  sometimes  for 
days,  seeming  to  make  no  effort  be 
yond  that  of  gently  playing  their  ten 
tacles  to  and  fro  (Fig.  92).  These 
tentacles  are  capable  of  immense  ex 
tension,  sometimes  to  ten  or  fifteen 
times  the  diameter  of  the  bell.  The 
proboscis  is  not  simple  as  in  the  Sar- 
sia,  but  looks  like  a  yellow  urn  sus 
pended  at  its  four  corners  from  the 
chymiferous  tubes.  The  oral  opening 
is  entirely  concealed  by  clusters  of 
shorter  tentacles  surrounding  the 
mouth  in  a  close  wreath,  on  which  the 
eggs  are  supported.  A  highly  magni 
fied  branch  of  the  Hydroid  stock  from 


Fig.  92.     Bougainvillia  ;  magnified. 

Fig.  93.    Hydrarium  of  Bougainvillia  ;  magnified. 


BOUQAINVILLIA. 


71 


which  this  Medusa  arises  is  represented  in  Fig.  93.     There  wo 
see  the  little  Jelly-fishes  in  different  degrees  of  development  on 

Fig.  94.  Fig.  95. 


the  stem,  while  in  Figs.  94  —  97  they  are  given  separately  and 
still  more  enlarged.  In  Fig.  94  the  outline  of  the  Jelly-fish  is 
still  oval,  the  proboscis  is  but  just  formed,  and  the  tentacles  ap- 


Fig.  96. 


Fig.  97. 


pear  only  as  round  swellings  or  knobs.  In  Fig.  95  a  depression 
has  taken  place  at  the  upper  end,  presently  to  be  an  opening, 
the  proboscis  is  enlarged,  and  the  tentacles  lengthened,  but  still 
turned  inward.  In  Fig.  96  the  appendages  of  the  proboscis  are 
quite  conspicuous,  the  tentacles  are  turned  outward,  and  the 


Figs.  94,  95,  96.    Medusae  buds  of  Fig  93,  in  different  degrees  of  development. 
Fig.  97.    Young  Medusa  just  freed  from  the  Hydroid  ;  magnified. 


72 


MARINE  ANIMALS    OF   MASSACHUSETTS    BAY. 


Jelly-fish  is  almost  ready  to  break  from  its  attachment,  having 
assumed  its  ultimate  outline.  Fig.  97  represents  it  just  after  it 
has  separated  from  the  stem,  when  it  has  only  two  tentacles  at 
each  cluster  and  simple  knobs  around  the  mouth,  instead  of  the 
complicated  branching  tentacles  of  the  adult. 

Tubularia.      (  Tubularia  Couihouyi  AG.) 

There  are  several  other  Tubularians  common  in  our  waters 
which  should  not  be  passed  over  without  mention,  although  as 
this  little  book  is  by  no  means  intended  as  a  complete  text-book, 
but  rather  as  a  volume  of  hints  for  amateur  collectors,  we  would 
avoid  as  much  as  possible  encumbering  it  with  many  names,  or 
with  descriptions  already  given  in  more  comprehensive  works. 
This  Tubularia  is  interesting,  however,  from  the  fact  that  the 
Medusae  buds  are  never  freed  from  the  stem,  and  do  not  develop 

Fig.  98.  Fig.  99. 


into  full-grown  Jelly-fishes,  but  always  remain  abortive.  Fig.  98 
represents  one  head  of  such  a  Hydroid  with  the  Medusas  buds 
pendent  from  it  in  a  thick  cluster,  while  in  Fig.  99  we  have  a 
few  of  them  sufficiently  magnified  to  show  that,  though  present 
ing  the  four  chymiferous  tubes,  they  are  otherwise  exceedingly 
simple  in  structure,  as  compared  with  the  free  Jelly-fishes. 


Fig.  98.    Tubularia  ;  magnified. 

Fig.  99.     Part  of  cluster  of  Medusas  of  Fig.  98  ;  magnified.     (Ayassiz.) 


HYDRACTINIA. 


73 


(Hydractinia  polyclina  AG.) 

This  is  another  Tubularian,  covering  the  surface  of  rocks  in 
tide-pools,  or  attaching  itself  upon  shells  inhabited  by  hermit 
crabs.  Indeed  it  was  upon  these  shells  that  the  Hydractinia  was 
first  noticed,  and  it  was  long  supposed  that  the  wanderings  to 
which  the  little  colony  was  thus  subjected  were  necessary  for  its 
healthy  development.  But  subsequent  observations  have  shown 
that  it  attaches  itself  quite  as  frequently  to  the  solid  rock  as  to 
these  nomadic  shells.  It  has  a  rosy  color,  and,  being  very  small, 
it  looks,  until  one  examines  it  closely,  more  like  a  thick  red  car 
pet  of  soft  moss,  than  like  a  colony  of  animals.  These  communi 
ties  are  distinct  in  sex,  the  fertile  individuals  in  each  being  either 
all  male  or  all  female.  In  Fig.  100  we  have  a  portion  of  a  fe 
male  colony,  representing  one  fertile  head,  in  which  the  buds  are 
crowded  with  Medusas  ;  one  sterile  head,  surrounded  by  its 


Fig.  100. 


Fig.  101. 


wreath  of  tentacles  ;  and  still  another  member  of  the  society 
whose  office  is  not  fully  understood,  unless  it  be  that  of  a  kind 
of  purveyor,  catching  food  for  the  rest.  Fig.  101  represents  the 
corresponding  individuals  taken  from  a  male  colony.  The  sex 
makes  little  difference  in  the  appearance  of  the  reproductive 
heads.  All  the  individuals  of  a  Hydractinia  colony  are  con 
nected  at  the  base  by  a  horny  network,  rising  occasionally 

Fig.  100.  Female  colony  of  Hydractinia  ;  a  sterile  individual,  b  fertile  individual  producing  female 
Medusae,  c  fertile  individual  with  globular  tentacles  without  Medusae,  d  efg  h  i  Medusae  in  different 
stages  of  growth,  o  mouth  tentacles.  (Ayassiz.") 

Fig.  101.     Male  colony  ;  a  a  sterile  individuals,  b  fertile   individuals  producing  male   Medusas,  d ; 
o  globular  tentacles,  t  slender  tentacles  of  sterile  individual.  (Ayassiz.) 
10 


74  MARINE   ANIMALS    OF   MASSACHUSETTS   BAY. 

into  points  of  a  conical  or  cylindrical  shape.  This  polymorphism 
among  the  Tubularians  is  another  evidence  of  the  relation  be 
tween  the  Siphonophorae,  or  floating  Hydroids,  and  the  fixed 
Hydroids. 


Hybocodon.    (Hybocodon  prolifer  AG.) 

Among  our  Medusae  derived  from  a  Tubularian  stock  is  the 
Hybocodon,  viz.  the  hunchbacked  Medusa  (Fig.  102),  a  singular 
little  Jelly-fish,  odd  and  unsymmetrical  in  shape,  as  its  name 
indicates,  and  interesting  from  its  relations  to  one  of  our  floating 
communities,  the  Nanomia,  presently  to  be  described.  Instead 
of  the  evenly  proportioned  bell  of  the  ordinary  Medusas,  the 
Hybocodon  has  a  one-sided  outline  (Fig.  102),  one  large  tentacle 
only  being  fully  developed,  while  the  others  remain  always  abor 
tive,  so  that  the  whole  weight  of  the  structure  is  thrown  on  one 
half  of  the  bell.  Upon  this  large  tentacle  small  Jelly-fishes, 
similar  to  the  original,  are  produced  by  budding,  this  process 


Fig.  102. 


Fig.  103. 


going  on  till  ten  or  twelve  such  Jelly-fishes  (Fig.  103)  may  be 

seen  suspended  from  the  tentacle.     Up  to  this  time  it  has  re- 
Fig.  102.    Unsymmetrical  free  Medusa  of  Hybocodon  ;  ro  chymiferous  tubes,  v  proboscis,  s  circular 

tube,  m  young  Medusae  at  base  of  long  tentacle  t.  (Ayassiz.) 

Fig.  103.    Medusa  bud  of  Hybocodon  ;  a  base  of  attachment,  o  proboscis,  c  circular  tube,  d  young 

Medusae  at  base  of  long  tentacle  t.  (rfyassiz.) 

Fig.  104.    Single  head  of  Hybocodon  Hydroid  ;  a  stem,  d  Medusae  buds,  o  tentacles  round  mouth. 

(Agassiz.) 


DYSMORPHOSA.  75 

i 

mained  connected  with  the  Hydroid  from  which  it  arises,  a  rather 
large  Tubularian,  usually  growing  singly  (Fig.  104),  and  of  a 
deep  orange-red  in  color.  But  at  this  stage  of  its  existence  it 
frees  itself,  and  leads  an  independent  life  hereafter,  swimming 
about  with  a  quick,  darting  motion.  In  the  account  of  the  Na- 
nomia,  the  homology  between  its  scale,  or  abortive  Medusa,  and 
the  Hybocodon,  is  traced  in  detail,  and  I  need  only  allude  to  it 
here.  Though  this  Medusa  is  so  peculiar  in  appearance,  the 
Tubularian  from  which  it  is  derived  is  very  like  the  Tubularia 
Coutlwuyi,  already  described.  This  is  one  of  the  instances  before 
alluded  to,  in  which  closely  allied  forms  give  rise  to  very  dissimi 
lar  ones,  or,  as  in  many  cases,  the  very  reverse  of  this  takes  place, 
and  closely  allied  forms  arise  from  very  dissimilar  ones. 

Dysmorphosa.     (Dysmorphosa  fulgurans  A.  AG.) 

Besides  the  budding  at  the  base  of  the  tentacle,  as  in  Hyboco 
don,  we  find  another  mode  of  development  among  Hydroid  Me 
dusae,  viz.  that  of  budding  from  the  proboscis.  One  of  our  most 
common  little  Jelly-fishes,  the  Dysmorphosa  (Fig.  105),  to  which 
we  owe  the  occasional  blue  phosphorescence  of  the  sea,  so  brilliant 
at  times,  buds  in  this  manner.  Fig.  105  represents  an  adult  Dys- 

Fig.  105.  Fig.  106. 


morphosa,  on  the  proboscis  of  which  may  be  seen  three  small  buds 
in  different  stages  of  development.  In  Fig.  106  the  proboscis  is 
more  enlarged,  showing  one  of  the  little  Jelly-fishes  similar  to 
the  parent,  just  ready  to  drop  off.  We  need  not  wonder  at  the 

Fig.  105.     Dysmorphosa  seen  in  profile  ;  magnified. 

Fig  106.     Magnified  proboscis  of  Dysmorphosa  with  young  Medusae  budding  from  it. 


76  MARINE    ANIMALS    OF   MASSACHUSETTS    BAY. 

immense  number  of  these  animals,  with  which  the  .sea  actually 
swarms  at  times,  when  we  know  that  as  fast  as  they  are 
dropped,  and  it  takes  but  a  few  days  to  complete  their  de 
velopment,  they  each  begin  the  same  process  ;  so  that  in  the 
course  of  a  week  or  ten  days  one  such  Medusa,  supposing  it  to 
have  produced  six  buds  only,  will  have  given  rise  to  forty-two 
Jelly-fishes,  thirty-six  of  which  may  be  equally  prolific  in  the 
same  short  period.  These  Medusa3  budding  thus,  and  swimming 
about,  carrying  their  young  with  them,  bear  such  a  close  resem 
blance  to  the  floating  communities  of  Hydroids  formerly  known  as 
Siphonophoras,  that  did  we  not  know  that  some  of  them  arise 
from  Tubularians,  it  would  be  natural  to  associate  them  with 
the  Siphonophora3. 

Nanomia.    (Nanomia  cam  A.  AG.) 

The  Nanomia  (Fig.  115),  our  free  floating  Hydroid,  consists, 
when  first  formed,  of  a  single  Hydra  containing  an  oblong  oil 
bubble  (Fig.  107).  The  whole  organization  of  such  a  Hydra  is 

limited  to  a  simple  digestive  cav 
ity  ;  it  has,  in  fact,  but  one  organ, 
and  one  function,  and  consists  of 
an  alimentary  sac  resembling  the 
probdscis  of  a  Medusa  (Fig.  107)  ; 
the  oil  bubble  is  separated  from 
it  by  a  transverse  partition,  and 
has  no  connection  with  the  cavity. 
Presently,  between  the  oil  bubble 
and  the  cavity  arise  a  number  of 
buds  of  various  character  (Fig.  108),  which  we  will  describe  one 
by  one,  beginning  with  those  nearest  the  oil  bubble,  since  these 
upper  members  of  the  little  swimming  community  bear  a  very  im 
portant  part  in  its  history.  The  infant  community  (Fig.  108) 
passes  rapidly  into  the '  stage  represented  in  Fig.  109,  and  then 
through  all  the  stages  intermediate  between  this  and  the  adult, 
shown  in  its  natural  size  in  Fig.  115.  The  upper  buds  en- 

Fig.  107.     Young  Nanomia  ;  magnified. 

Fig.  108.    Young  Nanomia  with  rudimentary  Medusas. 


NANOMIA. 


77 


large  gradually,  and  soon  take  upon  themselves  a  perfect  Me 
dusa  structure  (Fig.  110),  with  the  exception  of  the  proboscis, 
the  absence  of  which  is  easily  understood,  when  we  find  that 
these  Medusae  serve  the  purpose  of  locomotion  only,  having  no 


Fig.  109. 


Fig.  1JO. 


share  in  the  function  of  feeding  the  community,  so  that  a  diges 
tive  apparatus  would  be  quite  superfluous  for  them.  In  every 
other  respect  they  are  perfect  Medusae,  attached  to  the  Hydra  as 
the  Medusa  buds  always  are  when  first  formed,  having  the  (four) 
chymiferous  tubes,  characteristic  of  all  Hydroid  Medusae,  radi 
ating  from  the  centre  to  the  periphery ;  two  of  these  tubes 
are  very  winding,  as  may  be  seen  in  Fig.  110,  while  the  other 
pair  are  straight.  The  Medusae  themselves  are  heart-shaped 
in  form,  depressed  at  the  centre  of  the  upper  surface,  and 
bulging  on  either  side  into  wing-like  expansions,  where  they 
join  the  stem.  These  expansions  interlock  with  one  another, 
crossing  nearly  at  right  angles.  The  Medusae-like  buds  are  the 
swimming  bells ;  by  their  contractions,  alternately  taking  in  and 
throwing  out  the  water,  they  impel  the  whole  community  for 
ward,  so  that  it  seems  rather  to  move  like  one  animal,  than  like 
a  combination  of  individuals. 

Fig.  109.     Young  Nanomia,  older  than  Fig.  103. 

Fig.  110.    Heart-shaped  swimming  bell  of  Nanomia  ;  magnified. 


78  MARINE   ANIMALS    OF    MASSACHUSETTS    BAT. 

Besides  these  locomotive  members,  the  community  contains  three 
kinds  of  Hydrae  arising  as  buds  from  the  primitive  Hydra  below 
the  swimming  bells,  the  latter  remaining  always  nearest  the  oil 
bubble  at  the  top,  while  the  first  Hydra,  the  founder  of  the  com 
munity,  in  proportion  as  the  new  individuals  are  added,  is  gradu 
ally  pushed  downward,  and  remains  always  at  the  end  of  the 
string,  the  stem  of  which  is  formed  by  the  elongated  neck  of  the 
primitive  Hydra.  All  the  three  sets  of  Hydrae  have  certain  fea 
tures  in  common,  while  they  have  other  distinguishing  character 
istics  marking  them  as  distinct  individuals.  They  are  all  accom 
panied  by  triangular  shields  (Fig.  Ill),  arising  with  them  at  the 
Fig  U1  same  point  on  the  parent  stem,  and  all 

are  furnished  with  tentacles  hanging 
down  from  the  summit  of  the  Hydra  at 
the  side  opposite  the  shield.  These  facts 
are  important  to  remember,  since  we 
shall  presently  perceive,  upon  analyzing 
their  parts,  that  these  Hydras  have  a  close 
homology  to  the  Hybocodon.  The  ten 
tacles  differ  in  structure  as  well  as  in 
number  for  each  kind  of  Hydra.  Hav 
ing  shown  in  what  characters  they 
agree,  let  us  now  take  each  set  individ 
ually,  and  see  what  differences  they 
present. 

In  the  first  set  which  we  will  exam 
ine  the  Hydra  is  open-mouthed.  Like 
the  original  Hydra,  it  is  only  a  digestive 
tube,  similar  in  all  respects  to  the  proboscis  of  a  Medusa-disk. 
Its  only  function  is  that  of  feeding,  and  it  shows  a  laudable  fidel 
ity  to  its  calling,  being  very  constantly  and  earnestly  engaged  in 
the  work.  Let  us  add,  however,  that  in  this  instance  the  occu 
pation  is  not  a  wholly  selfish  one,  since  the  cavity  of  every  Hydra 
communicates  with  that  of  the  stem,  and  the  food  taken  in  at 
these  ever-gaping  mouths,  is  at  once  circulated  through  all  parts 
of  the  community,  with  the  exception  of  the  oil  bubble,  from 
which  it  is  excluded  by  the  transverse  partition  dividing  it  from 

Fig.  111.    Cluster  of  Medusae  with  tentacles  having  pendant  knobs. 


NANOMIA.  79 

all  the  lower  members  of  the  stock.  The  shields  share  in  this 
general  nourishment  of  the  compound  body  by  means  of  chymif- 
erous  tubes  extending  toward  the  outer  surface,  and  opening  into 
the  cavity  of  the  stem.  The  mouth  of  this  Hydra  is  very  flexible 
(Fig.  Ill),  expanding  and  contracting  at  the  will  of  the  animal, 
and  sometimes  acting  as  a  sucker,  fastening  itself,  leech-like,  on 
the  object  from  which  it  seeks  to  draw  its  sustenance.  (See  Fig. 
111.)  The  tentacles  attached  to  this  set  of  Hydrae  are  exceed 
ingly  long  and  delicate.  They  arise  in  a  cluster  at  the  upper 
and  inner  edge  of  the  Hydra,  just  at  its  point  of  juncture  with 
the  stem,  and  being  extremely  flexible  and  contractile,  their 
long  tendril-like  sprays  are  thrown  out  in  an  endless  variety  of 
attitudes.  (See  Fig.  115.)  Along  the  whole  length  of  this 
kind  of  tentacle  are  attached  little  pendent  knobs  at  even 
distances  ;  Fig.  112  represents  such  a  knob  greatly  magnified, 

Fig.  112.  Fig.  113. 


and  absolutely  paved  with  lasso-cells,  the  inner  and  smaller  ones 
being  surrounded  by  a  row  of  larger  ones. 

The  second  set  of  Hydrae  (Fig.  113),  are  also  open-mouthed, 
corresponding  with  those  described  above,  in  everything  except 
the  tentacles,  which  are  both  shorter  and  thicker,  and  are  coiled 
in  a  corkscrew-like  spiral.  These  are  thickly  studded  for  their 
whole  length  with  lasso-cells.  (See  Fig.  113.) 

In  the  third  and  last  set  of  Hydras   (Fig.  114),  the  mouth 

Fig.  112.    Magnified  pendent  knob. 

Fig.  113.    Medusa  with  corkscrew-shaped  tentacles. 


80  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

is  closed ;  they  have,  therefore,  no  share  in  feeding  the  com 
munity,  but  receive  their  nourishment  from  the  cavity  of  the  stem 
into  which  they  open.  They  differ  also  from  the  others  in  having 
a  single  tentacle  instead  of  a  cluster,  and  on  this  tentacle  the  lasso- 
rig.  iu.  ce^s  are  scattered  at  uneven  distances  (Fig.  114). 
The  special  function  of  these  closed  Hydras  is  yet  to 
be  explained  ;  they  have  oil  bubbles  at  their  upper 
end  (see  Fig.  Ill,  the  top  Hydra),  and  though  we 
have  never  seen  them  drop  off,  it  seems  natural  to 
suppose  that  they  do  separate  from  the  parent  stock, 
and  found  new  communities  similar  to  those  from 
which  they  arise. 

The  intricate  story  of  this  singular  compound  ex 
istence  does  not  end  here.  There  is  still  another  set 
of  individuals  whose  share  in  maintaining  the  life  of 
the  community  is  by  no  means  the  least  important. 
Little  bunches  of  buds,  of  a  different  character  from 
any  described  above,  may  be  seen  at  certain  distances 
along  the  lower  part  of  the  stem.  These  are  the  reproductive 
individuals.  They  are  clusters  of  imperfect  sexual  Medusae,  re 
sembling  the  rudimentary  Medusa3  of  Tubularia  (Fig.  99),  which 
are  never  freed  from  the  parent  stem,  but  discharge  their  contents 
at  the  breeding  season.  Like  many  other  compound  Hydroids, 
the  sexes  are  never  combined,  in  one  of  these  communities ;  they 
are  always  either  male  or  female,  and  as  those  with  female  buds 
have  not  yet  been  observed,  we  can  only  judge  by  inference  of 
their  probable  character.  From  what  is  already  known,  how 
ever,  of  Hydroid  communities  of  a  like  description,  we  suppose 
that  the  process  of  reproduction  must  be  the  same  in  these,  and 
that  the  female  stocks  of  Nanomia  give  birth  to  small  Jelly- 
fishes,  the  eggs  of  which  become  oil  bubbles,  similar  to  that  with 
which  our  little  community  began.  (Fig.  108.) 

By  the  time  all  these  individuals  have  been  added  along  the 
length  of  the  stem,  the  stem  itself  has  grown  to  be  about  three 
inches  long  (Fig.  115),  though  the  tentacles  hanging  from  the 
various  members  of  the  community  give  to  the  whole  an  appear 
ance  of  much  greater  length.  The  motion  of  this  little  string  of 

Fig.  114.     Medusa  with  a  simple  thread-like  tentacle. 


NANOMIA. 


81 


living  beings  is  most  graceful.  The  oil  bubble  (Fig.  116)  at  the 
upper  end  is  their  float ;  the  swimming  bells  immediately  below 
it  (Fig.  110),  by  the  convulsive  contractions  of  which  they  move 
along,  are  their  oars.  The  water  is  not  taken  in  and  expelled 


Fig.  115 


again  by  all  the  bells  at  once,  but  first  from  all  the  bells  on 
one  side,  beginning  at  the  lower  one,  and  then  from  all  those  on 
the  opposite  side,  beginning  also  at  the  lower  one  ;  this  alter- 


Fig.  115.     Adult  Nanoraia,  natural  size,  at  rest. 
11 


82  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

nate  action  gives  to  their  movements  a  swinging,  swaying  charac 
ter,  expressive  of  the  utmost  freedom  and  grace.  Whether  such 
rig.  lie.  a  little  community  darts  with  a  lightning-like  speed 
through  the  water,  or  floats  quietly  up  and  down, 
for  its  movements  are  both  rapid  and  gentle,  it 
always  sways  in  this  way  from  side  to  side.  Its 
beauty  is  increased  by  the  spots  of  bright  red 
scattered  along  the  length  of  the  stock  at  the 
base  and  tips  of  the  Hydra?,  as  well  as  upon  the 
tentacles.  The  movements  and  attitudes  of  the 
tentacles  are  most  various.  Sometimes  they 
shoot  them  out  in  straight  lines  on  either  side,  and  then  the 
aspect  of  the  whole  thing  reminds  one  of  a  tiny  chandelier  in 
which  the  coral  drops  make  the  pendants,  or  they  may  be  caught 
up  in  a  succession  of  loops  or  floating  in  long  streamers ;  indeed, 
there  is  no  end  to  the  fantastic  forms  they  assume,  ever  astonish 
ing  you  by  some  new  combination  of  curves.  The  prevailing 
hue  of  the  whole  community  is  rosy,  with  the  exception  of  the 
oil  bubble  or  float,  which  looks  a  bright  garnet  color  when  seen 
in  certain  lights. 

Let  us  now  compare  one  of  the  Hydras  hanging  from  the  stem 
(Fig.  113)  with  the  Hybocodon  (Fig.  102).  The  reader  will 
remember  the  unsymmetrical  bell  of  this  singular  Medusa,  one 
half  of  its  disk  more  largely  developed  than  the  other,  with  the 
proboscis  hanging  from  the  centre,  and  the  cluster  of  tentacles 
from  one  side.  Let  us  now  split  the  bell  so  as  to  divide  it  in  two 
halves  with  the  proboscis  hanging  between  them  ;  next  enlarge  the 
side  where  there  are  no  tentacles,  and  give  it  a  triangular  out 
line  ;  then  contract  the  opposite  side  so  as  to  draw  up  the  cluster 
of  tentacles  to  meet  the  base  of  the  proboscis,  and  what  have  we  ? 
The  proboscis  now  corresponds  to  the  Hydra  of  our  Nanomia, 
with  the  cluster  of  tentacles  attached  to  its  upper  edge  (Fig. 
113),  while  the  enlarged  half  of  the  bell  represents  the  shield. 
If  this  homology  be  correct  it  shows  that  the  Nanomia  is  not,  as 
some  naturalists  have  supposed  all  the  Siphonophores  to  be,  a 
single  animal,  its  different  parts  being  a  mere  collection  of  organs 
endowed  with  special  functions,  as  feeding,  locomotion,  repro- 

Fig.  116.    Oil  float  of  Nanomia  ;  greatly  magnified. 


PHYSALIA. 


83 


Fig.  117. 


duction,  &c.,  but  that  it  is  indeed  a  community  of  distinct  indi 
viduals  corresponding  exactly  to  the  polymorphous  Hydroids, 
whose  stocks  are  attached,  such  as  Hydractinia,  and  differing  from 
them  only  in  being  free  and  floating. 

The  homologies  of  the  Siphonophoras  or  floating  Hydroids, 
with  many  of  the  fixed  Hydroids,  is  perhaps  more  striking 
when  we  compare  the  earlier  stages  of 
their  growth.  Suppose,  for  instance,  that 
the  planula  of  our  Melicertum  (See  Fig. 
81)  should  undergo  its  development  with 
out  becoming  attached  to  the  ground, — 
what  should  we  then  have  ?  A  floating 
community  (Fig.  83),  including  on  the 
same  stock  like  the  Nanomia,  both  sterile 
and  fertile  Hydrae,  from  the  latter  of  which 
Medusae  bells  are  developed.  The  little 
Hydractinia  community  (Fig.  100),  in 
which  we  have  no  less  than  four  distinct 
kinds  of  individuals,  each  performing  a 
definite  distinct  function,  affords  a  still 
better  comparison. 

Physalia.    (Physalia  Arethusa  TIL.) 

Among  the  most  beautiful  of  the  Sipho- 
nophores,  is  the  well-known  Physalia  or 
Portuguese  man-of-war,  represented  in  Fig. 
117).  The  float  above  is  a  sort  of  crested 
sac  or  bladder,  while  the  long  streamers 
below  consist  of  a  number  of  individuals 
corresponding  in  their  nature  and  functions  to  those  composing  a 
Hydroid  community.  Among  them  are  the  fertile  and  sterile 
'Hydras  (Fig.  118),  the  feeders  and  Medusas  bells  (Fig.  119). 
The  Physalia  properly  belongs  to  tropical  waters,  but  sometimes 
floats  northward,  in  the  warm  current  of  the  Gulf  Stream,  and 
is  stranded  on  Cape  Cod.  When  found  so  far  from  their  home, 
however,  they  have  usually  lost  much  of  their  vividness  of  color ; 


Tig.  117.     Physalia ;  ab  air  sac  with  crest  c,  m  bunches  of  individuals,  n  central  tentacles,  1 1  ex 
panded  tentacles.  (Agassiz.) 


84 


MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 


to  judge  of  their  beauty  one  should  see  them  in  the  Gulf  of  Mex 
ico,  sailing  along  with  their  brilliant  float  fully  expanded,  their 
crest  raised,  and  their  long  tentacles  trailing  after  them. 


Fig.  118. 


Fig.  119. 


Velella.    (  VeUla  mutica  Bosc.) 

Another  very  beautiful  floating  Hydroid,  occasionally  caught 
in  our  waters,  though  its  home  is  also  far  to  the  south,  is  the 


Fig.  120. 


Fig.  121. 


Velella  (Fig.  120).  It  is  bright  blue  in  color,  and  in  form  1101 
unlike  a  little  flat  boat  with  an  upright  sail.  Its  Medusa 
(Fig.  121)  resembles  so  much  that  of  some  of  our  Tubu- 
larians,  that  it  has  actually  been  removed  on  this  account  from 
the  old  group  of  Siphonophorae,  and  placed  next  the  Tubula- 
rians  ;  another  evidence  of  the  close  affinity  between  the  former 
and  the  Hydro-ids. 

Fig.  118.  Bunch  of  Hydrse  ;  a  base  of  attachment,  bb  b  single  Hydrae,  c  c  tentacles.  (Agassiz.) 

Fig.  119.  Bunch  of  Hydrae  ;  cluster  of  Medusae  ;   b  b  Hydrae  with  tentacles,  c  d  bunches  of  Medusae. 
(Ayassiz.) 

Fig.  120.  Velella  ;  m  so-called  mouth,  a  tentacles.  (Agassiz.) 

Fig.  121.  Free  Medusae  of  Velella  ;  a  proboscis,  U  chymiferous  tube,  c  circular  tube.  (Ayassiz.) 


MODE    OF    CATCIIIX3    JELLY-FISHES.  85 


MODE   OF   CATCHING  JELLY-FISHES. 

NOT  the  least  attractive  feature  in  the  study  of  these  animals, 
is  the  mode  of  catching  them.     We  will  suppose  it  to  be  a  warm, 
still   morning  at  Nahant,  in  the  last  week  of  August,  with  a 
breath  of  autumn  in  the  haze,  that  softens  the  outlines  of  the  op 
posite  shore,  and  makes  the  horizon  line  a  little  dim.     It  is  about 
eleven  o'clock,  for  few  of  the  Jelly-fishes  are  early  risers;  they  like 
the  warm  sun,  and  at  an  earlier  hour  they  are  not  to  be  found 
very  near  the  surface.     The  sea  is  white  and  glassy,  with  a  slight 
swell  but  no  ripple,  and  seems  almost  motionless  as  we  put  off  in 
a  dory  from  the  beach  near  Saunders's  Ledge.     We  are  provided 
with  two  buckets,  one  for  the  larger  Jelly-fishes,  the  Zygodactyia, 
Aurelia,  &c.,  the  other  for  the  smaller  fry,  such  as  the  various 
kinds  of  Ctenpphorae,  the  Tima,  Melicertum,  <fec.     Beside  these, 
we  have  two  nets  and  glass  bowls,  in  which  to  take  up  the  more 
fragile  creatures  that  cannot  bear  rough  handling.     A  bump  or 
two  on  the  stones  before  we  are  fairly  launched,  a  shove  of  the 
oar  to  keep  the  boat  well  out  from  the  rocks  along  which  we 
skirt  for  a  moment,  and  now  we  are  off.     We  pull  around  the 
point  to  our  left  and  turn  toward  the  Ledge,  filling  our  buckets 
as  we  go.     Now  we  are   crossing  the  shallows  that  make  the 
channel  between  the  inner  and  outer  rocks  of  Saunders's  Ledge. 
Look  down,  —  how  clear  the  water  is  and  how  lovely  the  sea 
weeds,   above  which  we   are   floating,  dark   brown  and  purple 
fronds  of  the  Ulvae,  and  the  long  blades  of  the  Laminaria  with 
mossy  green  tufts  between.     As  we  issue  from  this  narrow  pas 
sage  we  must  be  on  the  watch,  for  the  tide  is  rising,  and  may 
come  laden  with  treasures,  as  it  sweeps  through  it.     A  sudden 
cry  from  the  oarsman  at  the   bow,  not  of  rocks  or   breakers 
ahead,  but  of  "A  new  Jelly-fish  astern! "     The  quick  eye  of  the 
naturalist  of  the  party  pronounces  it  unknown  to  zoologists,  un- 
described  by  any  scientific  pen.     Now  what  excitement !     "  Out 
with  the  net !  —  we  have  passed  him  !  he  has  gone  down  !  no, 
there  he  is  again  !  back  us  a  bit."     Here  he  is  floating  close  by 
us ;  now  he  is  within  the  circle  of  the  net,  but  he  is  too  delicate 


86  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

to  be  caught  safely  in  that  way,  so,  while  one  of  us  moves  the 
net  gently  about,  to  keep  him  within  the  space  enclosed  by  it, 
another  slips  the  glass  bowl  under  him,  lifts  it  quickly,  and  there 
is  a  general  exclamation  of  triumph  and  delight,  —  we  have  him. 
And  now  we  look  more  closely  ;  yes,  decidedly  he  is  a  novelty  as 
well  as  a  beauty.  (See  Fig.  122,  Ptychogena  lactea  A.  Ag.)  Those 

Fig.  122. 


white  mossy  tufts  for  ovaries  are  unlike  anything  we  have  found 
before  (Fig.  123),  and  not  represented  in  any  published  figures 
of  Jelly-fishes.  We  float  about  here  for  a  while,  hoping  to  find 
more  of  the  same  kind,  but  no  others  make  their  appearance, 
and  we  keep  on  our  way  to  East  Point,  where  there  is  a  capital 
fishing  ground  for  Medusae  of  all  sorts.  Here  two  currents  meet, 
and  the  Jelly-fishes  are  stranded  as  it  were  along  the  line  of 
juncture,  able  to  move  neither  one  way  nor  the  other.  At  this 
spot  the  sea  actually  swarms  with  life  ;  one  cannot  dip  the  net 
into  the  water  without  bringing  up  Pleurobrachia,  Bolina,  Idyia, 
Melicertum,  <fec.,  while  the  larger  Zygodactyla  and  Aurelia  float 
about  the  boat  in  numbers.  These  large  Jelly-fishes  produce  a 
singular  effect  as  one  sees  them  at  some  depth  beneath  the  water ; 

Fig.  122.     Ptychogena,  natural  size. 


MODE    OF    CATCHING    JELLY-FISHES.  87 

the  Aurelise,  especially,  with  their  large  white  disks,  look  like 
pale  phantoms  wandering  about  far  below  the  surface  ;  but  they 
constantly  float  upward,  and  if  not  too  far  out  of  reach,  one  may 
bring  them  up  by  stirring  the  water  under  them  with  the  end  of 
the  oar. 

When  we  have  passed  an  hour  or  so  floating  about  just 
beyond  East  Point,  and  have  nearly 
filled  our  buckets  with  Jelly-fishes  of 
all  sizes  and  descriptions,  we  turn 
and  row  homeward.  The  buckets 
look  very  pretty  as  they  stand  in  the 
bottom  of  the  boat  with  the  sun 
shine  lighting  up  their  living  con 
tents.  The  Idyia  glitters  and  spar 
kles  with  ever-changing  hues,  the 
Pleurobrachiae  dart  about,  trailing 
their  long  graceful  tentacles  after 
them,  the  golden  Melicerta  are  kept 
in  constant  motion  by  their  quick, 
sudden  contractions,  and  the  deli 
cate  transparent  Tima  floats  among 
them  all,  not  the  less  beautiful  be 
cause  so  colorless.  There  is  an  un 
fortunate  Idyia,  who,  by  some  mis 
take,  has  got  into  the  wrong  bucket 
with  the  larger  Jelly-fish,  where  a  Zy- 
godactyla  has  entangled  it  among  his  tentacles  and  is  quietly 
breakfasting  upon  it. 

During  our  row  the  tide  has  been  rising,  and  as  we  near  the 
channel  of  Saunders's  Ledge,  it  is  running  through  more  strongly 
than  before,  and  at  the  entrance  of  the  shallows  a  pleasant  sur 
prise  is  prepared  for  us  ;  no  less  than  half  a  dozen  of  our  new 
friends  (the  Ptychogena  as  he  has  been  baptized),  come  to  look 
for  their  lost  companion  perhaps,  await  us  there,  and  are  pres 
ently  added  to  our  spoils.  We  reach  the  shore  heavily  laden 
with  the  fruits  of  our  morning's  excursion. 

The  most  interesting  part  of  the  work  for  the  naturalist   is 

Fig.  123.    Ovary  of  Ptychogena  5    magnified. 


88  MARINE   ANIMALS    OF    MASSACHUSETTS    BAY. 

still  to  come.  On  our  return  to  the  Laboratory,  the  contents  of 
the  buckets  are  poured  into  separate  glass  bowls  and  jars  ;  hold 
ing  them  up  against  the  light,  we  can  see  which  are  our  best 
and  rarest  specimens  ;  these  we  dip  out  in  glass  cups  and  place 
by  themselves.  If  any  small  specimens  are  swimming  about  at 
the  bottom  of  the  jar,  and  refuse  to  come  within  our  reach,  there 
is  a  very  simple  mode  of  catching  them.  Dip  a  glass  tube  into  the 
water,  keeping  the  upper  end  closed  with  your  finger,  and  sink  it 
till  the  lower  end  is  just  above  the  animal  you  want  to  entrap ; 
then  lift  your  finger,  and  as  the  air  rushes  out  the  water  rushes 
in,  bringing  with  it  the  little  creature  you  are  trying  to  catch. 
When  the  specimens  are  well  assorted,  the  microscope  is  taken 
out,  and  the  rest  of  the  day  is  spent  in  studying  the  new  Jelly- 
fishes,  recording  the  results,  making  notes,  drawings,  <fec. 

Still  more  attractive  than  the  rows  by  day  are  the  night  ex 
peditions  in  search  of  Jelly-fishes.  For  this  object  we  must 
choose  a  quiet  night,  for  they  will  not  come  to  the  surface  if  the 
water  is  troubled  ;  Nature  has  her  culminating  hours,  and  she 
brings  us  now  and  then  a  day  or  night  on  which  she  seems  to  have 
lavished  all  her  treasures.  It  was  on  such  a  rare  evening,  at  the 
close  of  the  summer  of  1882,  that  we  rowed  over  the  same  course 
by  Saundcrs's  Ledge  and  East  Point  described  above.  .The 
August  moon  was  at  her  full,  the  sky  was  without  a  cloud,  and 
we  floated  on  a  silver  sea  ;  pale  streamers  of  the  aurora  quivered 
in  the  north,  and  notwithstanding  the  brilliancy  of  the  moon,  they 
too  cast  their  faint  reflection  in  the  ocean.  We  rowed  quietly 
along  past  the  Ledge,  past  Castle  Rock,  the  still  surface  of  the 
water  unbroken,  except  by  the  dip  of  the  oars  and  the  ripple  of 
the  boat,  till  we  reached  the  line  off  East  Point,  where  the  Jelly- 
fishes  are  always  most  abundant,  if  they  are  to  be  found  at  all. 
Now  dip  the  net  into  the  water.  What  genie  under  the  sea  has 
wrought  this  wonderful  change  ?  Our  dirty,  torn  old  net  is  sud 
denly  turned  to  a  web  of  gold,  and  as  we  lift  it  from  the  water 
heavy  rills  of  molten  metal  seem  to  flow  down  its  sides  and  col 
lect  in  a  glowing  mass  at  the  bottom.  The  truth  is,  the  Jelly- 
fishes,  so  sparkling  and  brilliant  in  the  sunshine,  have  a  still  love 
lier  light  of  their  own  at  night ;  they  give  out  a  greenish  golden 
light  as  brilliant  as  that  of  the  brightest  glow-worm,  and  on  a 


MODE    OF    CATCHING    JELLY-FISHES.  89 

calm  summer  night,  at  the  spawning  season,  when  they  come  to 
the  surface  in  swarms,  if  you  do  but  dip  your  hand  into  the 
water  it  breaks  into  sparkling  drops  beneath  your  touch.  There 
are  no  more  beautiful  phosphorescent  animals  in  the  sea  than 
the  Medusae  ;  it  would  seem  that  the  expression,  "  rills  of  molten 
metal  "  could  hardly  apply  to  anything  so  impalpable  as  a  Jelly 
fish,  but,  although  so  delicate  in  structure,  their  gelatinous  disks 
give  them  a  weight  and  substance  ;  and  at  night,  when  their 
transparency  is  not  perceived,  and  their  whole  mass  is  aglow  with 
phosphorescent  light,  they  truly  have  an  appearance  of  solidity 
which  is  most  striking,  when  they  are  lifted  out  of  the  water  and 
flow  down  the  sides  of  the  net. 

The  various  kinds  present  very  different  aspects  ;  wherever 
the  larger  Atirelise  and  Zygodactyla3  float  to  the  surface,  they 
bring  with  them  a  dim  spreading  halo  of  light,  the  smaller 
Ctenophorae  become  little  shining  spheres,  while  a  thousand 
lesser  creatures  add  their  tiny  lamps  to  the  illumination  of 
the  ocean  ;  for  this  so-called  phosphorescence  of  the  sea  is  by 
no  means  due  to  the  Jelly-fishes  alone,  but  is  also  produced 
by  many  other  animals,  differing  in  the  color  as  well  as  the  in 
tensity  of  their  light,  and  it  is  a  curious  fact  that  they  seem 
to  take  possession  of  the  field  by  turns.  You  may  row  over  the 
same  course,  which  a  few  nights  since  glowed  with  a  greenish 
golden  light  wherever  the  surface  of  the  water  was  disturbed,  and 
though  equally  brilliant,  the  phosphorescence  has  now  a  pure 
white  light.  On  such  an  evening,  be  quite  sure  that  when  you 
empty  your  buckets  on  your  return  and  examine  their  contents 
you  will  find  that  the  larger  part  of  your  treasures  are  small 
Crustacea  (little  shrimps).  Of  course  there  will  be  other  phos 
phorescent  creatures,  Jelly-fishes,  <fec.,  among  them,  but  the  pre- 
dominant  color  is  given  by  these  little  Crustacea.  On  another 
evening  the  light  will  have  a  bluish  tint,  and  then  the  phosphores 
cence  is  principally  due  to  the  Dysmorphosa  (Fig.  105). 

Notwithstanding  the  beauty  of  a  moonlight  row,  if  you  would 
see  the  phosphorescence  to  greatest  advantage  you  must  choose  a 
dark  night,  when  the  motion  of  your  boat  sets  the  sea  on  fire 
around  you,  and  a  long  undulating  wave  of  light  rolls  off  from 
your  oar  as  you  lift  it  from  the  water.  On  a  brilliant  evening 

12 


90  MARINE   ANIMALS    OF    MASSACHUSETTS    BAY. 

this  effect  is  lost  in  a  great  degree,  and  it  is  not  until  you  dip 
your  net  fairly  under  the  moonlit  surface  of  the  sea,  that  you 
are  aware  how  full  of  life  it  is.  Occasionally  one  is  tempted  out 
by  the  brilliancy  of  the  phosphorescence,  when  the  clouds  are  so 
thick  that  water,  sky,  and  land  become  one  indiscriminate  mass 
of  black,  and  the  line  of  rocks  can  be  discerned  only  by  the  vivid 
flash  of  greenish  golden  light,  when  the  breakers  dash  against 
them.  At  such  times  there  is  something  wild  and  weird  in  the 
whole  scene,  which  at  once  fascinates  and  appalls  the  imagination ; 
one  seems  to  be  rocking  above  a  volcano,  for  the  surface  around 
is  intensely  black,  except  where  fitful  flashes  or  broad  waves  of 
light  break  from  the  water  under  the  motion  of  the  boat  or  the 
stroke  of  the  oars.  It  was  on  a  night  like  this,  when  the  phos 
phorescence  was  unusually  brilliant,  and  the  sea  as  black  as  ink, 
the  surf  breaking  heavily  and  girdling  the  rocky  shore  with  a  wall 
of  fire,  that  our  collector  was  so  fortunate  as  to  find  in  the  rich 
harvest  he  brought  home  the  entirely  new  and  exceedingly  pretty 
little  floating  Hydroid,  described  under  the  name  of  Nanomia 
(Fig.  115).  It  was  in  its  very  infancy  (Fig.  108),  a  mere  bub 
ble,  not  yet  possessed  of  the  various  appendages  which  eventually 
make  up  its  complex  structure  ;  but  it  was  nevertheless  very  im 
portant  to  have  seen  it  in  this  early  stage  of  its  existence,  since, 
when  a  few  full-grown  specimens  were  found  in  the  autumn, 
which  lived  for  some  days  in  confinement  and  quietly  allowed 
their  portraits  to  be  taken  (see  Fig.  115),  it  was  easy  to  connect 
the  adult  animal  with  its  younger  phase  of  life  and  thus  make  a 
complete  history. 

Marine  phosphorescence  is  no  new  topic,  and  we  have  dwelt  too 
long,  perhaps,  upon  a  phenomenon  that  every  voyager  has  seen, 
and  many  have  described  ;  but  its  effect  is  very  different,  when 
seen  from  the  deck  of  a  vessel,  from  its  appearance  as  one  floats 
through  its  midst,  distinguishing  the  very  creatures  that  produce 
it,  and  any  account  of  the  Medusae  which  did  not  include  this 
most  characteristic  feature  would  be  incomplete. 


ECHINODERMS. 

/    . 

Library* 

ECHINODERMS.       V  9 

®t  California. 

^Sfcr— ..      ,. . 

OUR  illustrations  and  descriptions  of  Ecliinoderms  are  scanty 
in  comparison  to  those  of  the  preceding  class  ;  for  while,  in  con 
sequence,  perhaps,  of  the  combined  influence  of  the  Gulf  Stream 
and  the  cold  arctic  current  on  the  New  England  shore,  Acalephs 
are  largely  represented  in  our  waters,  our  marine  fauna  is 
meagre  in  Ecliinoderms.  But  although  we  have  few  varieties, 
those  which  do  establish  themselves  on  a  coast  seemingly  so 
ungenial  for  others  of  their  kind,  such  as  the  Echinus,  and  our 
common  Star-fish,  for  instance,  thrive  well  and  are  very  abun 
dant.  The  class  of  Ecliinoderms  includes  five  orders,  viz.  CRI- 
NOIDS,  OPHIURANS,  STAR-FISHES,  SEA-URCHINS,  and  HOLOTHURIANS. 
The  animals  composing  these  orders  differ  so  widely  in  appear 
ance  that  it  was  very  long  before  their  true  relations  were  de 
tected,  and  it  was  seen  that  all  their  external  differences  were 
united  under  a  common  plan.  Let  us  compare,  for  instance,  the 
worm-like  Holothurians  (Figs.  124, 126, 127)  with  all  the  host  of 
Star-fishes  (Figs.  142, 146, 147)  and  Sea-urchins  (Figs.  131, 139), 
or  compare  the  radiating  form  of  the  Star-fish,  its  arms  spreading 
in  every  direction,  with  the  close  spherical  outline  of  the  Sea- 
urchin,  or  the  Crinoid  floating  at  the  end  of  a  stem  (Fig.  152) 
with  either  of  these,  and  we  shall  cease  to  wonder  that  naturalists 
failed  to  find  at  once  a  unity  of  idea  under  all  these  varieties  of 
execution.  And  yet  the  fundamental  structure  of  the  class  of 
Ecliinoderms  is  represented  as  distinctly  by  any  one  of  its  five 
orders  as  by  any  other,  and  is  absolutely  identical  in  all.  They 
differ  only  by  trifling  modifications  of  development. 

In  Ecliinoderms  as  a  class,  the  body  presents  three  regions  dif 
fering  in  structure,  and  on  the  greater  or  less  development  of 
these  regions  or  systems,  as  we  may  call  them,  their  chief  differen 
ces  are  based.  Take,  for  instance,  the  dorsal  system,  the  nature 
of  which  is  explained  by  the  name,  indicating  of  course  the  back 
of  the  animal,  though  it  does  not  necessarily  imply  the  upper 
side  of  the  body,  since  some  of  the  Ecliinoderms,  as  the  stemmed 
Crinoids,  for  example,  carry  the  dorsal  side  downward,  while 


92  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

the  Star-fishes  and  Sea-urchins  carry  it  upward,  and.  the  Holothu- 
rians,  moving  with  the  mouth  forward,  have  the  dorsal  system 
at  the  opposite  end  of  the  body.  Whatever  the  natural  attitude 
of  the  animal,  however,  and  the  consequent  position  of  the  dorsal 
region,  it  exists  alike  in  all  the  five  orders,  though  it  has  not  the 
same  extent  and  importance  in  each.  But  in  all  it  is  made  up  of 
similar  parts,  bears  the  same  relation  to  the  rest  of  the  body,  has 
the  same  share  in  the  general  economy  of  the  animal.  And 
though  when  we  compare  the  spreading  back  of  a  Star -fish  with 
the  small  area  on  the  top  of  a  Sea-urchin,  where  all  the  zones 
unite,  we  may  not  at  once  see  the  correspondence  between  them, 
yet  a  careful  comparison  of  all  their  structural  details  shows  that 
they  are  both  built  with  the  same  elements  and  represent  the 
same  region,  though  it  is  stretched  to  the  utmost  in  the  one  case, 
and  greatly  contracted  in  the  other. 

This  being  true  of  the  dorsal  system,  let  us  look  at  another 
equally  important  structural  feature  in  this  class.  All  Echino- 
derms  have  locomotive  organs  peculiar  to  themselves,  a  kind 
of  suckers  which  may  be  more  or  less  numerous,  larger  or 
smaller,  in  different  species,  but  are  always  appendages  of  the 
same  character.  These  are  variously  distributed  over  the  body, 
but  always  with  a  certain  regularity  occupying  definite  spaces, 
shown  by  investigation  to  be  homologous  in  all.  For  instance, 
the  rays  of  the  Star-fish  correspond  in  every  detail  on  their  under 
side,  along  which  the  locomotive  suckers  run,  with  the  zones  on 
the  Sea-urchin,  from  end  to  end  of  which  the  suckers  are  ar 
ranged  ;  and  the  same  is  equally  true  of  the  distribution  of  the 
suckers  on  the  Holothurians,  Ophiurans,  and  Crinoids,  though, 
as  most  persons  are  less  familiar  with  these  orders  than  with 
the  other  two,  it  might  not  be  so  easy  to  point  out  the  coin 
cidence  to  our  readers.  These  suckers  are  called  the  ambu 
lacra,  the  lines  along  which  they  run  are  called  the  ambulacral 
rows  or  zones,  while  the  system  of  locomotion  as  a  whole  is 
known  as  the  ambulacral  system.  Since  these  organs  are  thus 
regularly  distributed  over  the  body  in  distinct  zones  or  rows,  it 
follows  that  the  latter  must  be  divided  by  intervening  spaces. 
These  intervals  are  called  the  interambulacral  spaces  ;  but  while 
in  some  orders  they  are  occupied  by  larger  plates  and  prominent 


ECHINODERMS.  93 

spines,  as  in  the  Sea-urchin  and  Star-fish,  in  others  they  are  either 
comparatively  insignificant  or  completely  suppressed,  as  in  the 
Crinoids  and  Ophiurans.  Such  are  the  three  regions  or  systems 
which  by  their  greater  or  less  development  introduce  an  almost 
infinite  variety  of  combinations  into  this  highest  class  of  Radi 
ates.  It  may  not  be  amiss  before  proceeding  further  to  compare 
the  five  orders  with  reference  to  this  point,  and  see  which  of 
these  three  systems  has  the  preponderance  in  each  one. 

Taking  the  orders  in  their  rank  and  beginning  with  the  lowest, 
we  find  in  the  Crinoids  that  the  dorsal  system  preponderates, 
being  composed  of  highly  complicated  plates,  and  developed  to 
such  a  degree  as  to  form  in  many  instances  a  stem  by  which  the 
animal  is  attached  to  the  ground,  while  the  ambulacral  system  is 
limited  to  a  comparatively  small  area,  and  the  interanibulacral 
system  is  wanting.  The  order  of  Crinoids  has  diminished  so 
much  in  modern  geological  times  that  we  must  consult  its 
fossil  forms  in  order  to  understand  fully  the  peculiar  adaptation 
of  the  Echinoderm  plan  in  this  group. 

In  the  Ophiurans,  the  dorsal  system  is  still  large,  and  though 
it  no  longer  stretches  out  to  form  a  stem,  it  folds  over  on  the  un 
der  side  of  the  animal  so  as  to  enclose  entirely  the  ambulacral 
system,  forming  a  kind  of  shield  for  the  arms.  Here  also  the  in 
teranibulacral  system  is  wanting. 

In  the  Star-fishes  the  dorsal  system  encroaches  less  upon  the 
structure  of  the  animal.  The  back  and  oral  side  here  correspond 
exactly  in  size,  and  though  the  flat  leathery  upper  surface  of 
the  animal,  covered  with  spines,  serves  as  a  protection  to  the 
delicate  ambulacral  suckers  which  find  their  way  between  the 
rows  of  small  plates  along  the  under  side  of  the  arms,  yet  it  does 
not  enfold  them  as  in  the  Ophiurans.  On  the  contrary,  in  the 
Star-fishes  the  ambulacral  rows  are  protected  on  either  side  by  a 
row  of  the  so-called  interambulacral  plates,  through  which  no 
suckers  pass. 

In  the  Sea-urchin,  the  dorsal  system  is  contracted  to  a  mini 
mum,  forming  a  small  area  on  the  top  of  the  animal,  the  rows  of 
interambulacral  plates  which  are  separated  and  lie  on  either  side 
of  the  ambulacra  in  the  Star-fish  being  united  in  the  Sea-urchin, 
and  both  the  ambulacral  and  the  interambulacral  systems  bent 


94  MARINE   ANIMALS    OF    MASSACHUSETTS    BAY. 

upward,  meeting  in  the  small  dorsal  area  above,  so  as  to  form  a 
spherical  outline.  Here  the  ambulacral  and  interambulacral 
systems  have  taken  a  great  preponderance  over  the  dorsal  system, 
and  the  same  is  the  case  with  the  Holothurians,  in  which  the 
same  structure  is  greatly  elongated,  the  dorsal  system  being 
thus  pushed  out  as  it  were  to  the  end  of  a  cylinder,  while  the 
ambulacral  and  interambulacral  systems  run  along  its  whole 
length.  All  Echinoderms  without  exception  have  ambulacral 
tubes,  even  though  in  some  there  are  no  external  ambulacral 
suckers  connected  with  them. 

There  is  one  organ  peculiar  to  the  class  of  Echinoderms,  the 
general  structure  of  which  may  be  described  here,  since  it  is 
common  to  them  all,  with  the  exception  of  the  Crinoids,  the 
anatomy  of  which  is,  however,  so  imperfectly  understood,  that 
we  are  hardly  justified  in  assuming  that  it  does  not  exist  even 
in  that  order.  This  organ  is  known  as  the  madreporic  body  ; 
it  is  a  small  sieve  or  limestone  filter  opening  into  a  tube  or 
canal ;  by  means  of  this  tube,  which  connects  with  the  am 
bulacral  system,  the  water  from  without,  first  filtered  through 
the  madreporic  body  and  thus  freed  from  any  impurities,  is  con 
veyed  to  the  ambulacra.  In  the  more  detailed  account  of  the 
different  orders  we  shall  see  what  is  the  position  of  this  singular 
organ  in  each  group,  and  how  it  is  adapted  in  them  all  to  their 
special  structure.  The  development  of  Echinoderms  forms  one 
of  the  most  wonderful  chapters  in  the  annals  of  Natural  History. 
Marvellous  as  is  the  embryonic  history  of  the  Acalephs,  including 
all  the  different  aspects  they  assume  in  the  cycle  of  their  growth, 
it  is  thrown  into  the  shade  by  the  transformations  which  Echino 
derms  undergo  before  assuming  their  adult  condition.  This 
singular  mode  of  development,  although  it  has  features  recalling 
the  development  of  Jelly-fishes  from  Hydroids,  is  nevertheless 
entirely  distinct  from  it,  and  is  known  only  in  the  class  of  Echi 
noderms.  As  the  whole  story  is  given  at  length  in  the  chapter 
on  the  embryology  of  the  Echinoderms,  we  need  only  allude  to  it 
here  in  general  terms.  We  owe  the  discovery  of  this  remarkable 
process  to  Johannes  Miiller,  one  of  the  greatest  anatomists  of 
this  century. 


HOLOTHURIANS. 


95 


Fig.  124. 


HOLOTHUKIANS.  rftr^ 

Synapta.      (Synapta  tennis  AYRES.) 

THIS  is  one  of  the  most  curious  of  the  Holothurians,  and  easily 
observed  on  account  of  its  transparency,  which  allows  us  to  see  its 
internal  structure.  It  has  a 
long  cylindrical  body  (Fig. 
124)  along  the  length  of 
which  run  the  five  rows  of 
ambulacra,  which  are  in  this 
instance  closed  tubes  with 
out  any  projecting  suckers 
or  locomotive  organs  of  any 
kind  attached  to  them,  so 
that  the  name  is  retained 
only  on  account  of  their  cor 
respondence  in  position,  and 
not  from  any  similarity  of 
function  to  the  ambulacra  in 
Star-fishes  and  Sea-urchins. 
But  though  the  ambulacra 
in  Synapta  are  in  fact  mere 
water-tubes  like  the  vertical 
tubes  in  the  Ctenophorse,  by 
means  of  which  the  water, 
first  filtered  through  the 
madreporic  body,  circulates 
along  the  skin,  they  are  as 
organs  perfectly  homologous 

with  the  ambulacra  in  all  other  Echinoderms.  The  mouth  has 
a  circular  tube  around  the  aperture,  and  a  wreath  of  branching 
tentacles  encircling  it.  The  habits  of  these  animals  are  singular. 
They  live  in  very  coarse  mud,  but  they  surround  themselves  with 
a  thin  envelope  of  finer  sand,  which  they  form  by  selecting  the 

Fig.  124.     Synapta,  natural  size. 


96  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

smaller  particles  with  their  tentacles,  and  making  a  ring  around 
their  anterior  extremity.  This  ring  they  then  push  down  along 
the  length  of  the  body,  and  continue  this  process,  adding  ring 
after  ring,  till  they  have  entirely  encircled  themselves  with  a 
sand  tube.  They  move  the  rings  down  partly  by  means  of  con 
tractions  of  the  body,  but  also  by  the  aid  of  innumerable  append 
ages  over  the  whole  surface.  To  the  naked  eye  these  appendages 
appear  like  little  specks  on  the  skin  ;  but  under  the  microscope 
they  are  seen  to  be  warts  projecting  from  the  surface,  each  one 
containing  a  little  anchor  with  the  arms  turned  upward  (Fig. 
125).  Around  the  mouth  these  warts  are  larger,  but  do  not 
contain  any  anchors.  It  will  be  seen  here 
after  that  these  appendages  are  homologous 
with  certain  organs  in  other  Holothurians, 
the  warts  with  the  anchors  correspond 
ing  to  the  limestone  pavement  covering 
or  partially  covering  the  surface  of  the 
Cuvieria,  for  instance,  while  those  without 
anchors  correspond  to  the  so-called  false 
ambulacra  in  Pentacta.  By  means  of  these 
appendages,  though  aided  also  by  the  con 
tractions  of  the  body,  the  Synaptae  move 
through  the  mud  and  collect  around  them 
selves  the  sand  tube  in  which  they  are  en 
cased.  Their  food  is  very  coarse  for  animals  so  delicate  in  struc 
ture.  When  completely  empty  of  food  they  are  white,  perfectly 
transparent,  and  the  spiral  tube  forming  the  digestive  cavity  may 
be  seen  wound  up  and  hanging  loosely  in  the  centre  for  the  whole 
length  of  the  body.  In  such  a  condition  it  is  of  a  pale  yellow 
color.  But  look  at  one  that  is  gorged  with  food.  The  whole 
length  of  the  alimentary  canal  is  then  crowded  with  sand,  peb 
bles,  and  shells,  distinctly  seen  through  the  transparent  skin,  and 
giving  a  dark  gray  color  to  the  whole  body.  They  swallow  the 
sand  for  the  sake  of  the  nutritious  substance  it  contains,  and 
having  assimilated  and  digested  this,  they  then  eject  the  harder 
materials.  The  motion  of  the  body  in  consequence  of  its  contrac- 

Fig.  125.    Anchor  of  Synapta  5  a  anchor,  w  plate  upon  which  anchor  is  attached  5  greatly  mag- 
niaed. 


CAUDINA. 


97 


tions  is  much  like  that  of  leeches,  and  on  this  account  these 
Synaptae  were  long  supposed  to  be  a  transition  type  between  the 
Radiates  and  worms.  The  body  grows  to  a  great  length,  often 
half  a  yard  and  more,  but  constantly  drops  large  portions  from 
its  posterior  part,  by  means  of  its  own  contractions,  or  breaks  it 
self  up  by  the  expulsion  of  the  intestines,  which  are  very  readily 
cast  out.  The  tentacles  are  hollow,  consisting  of  a  central  rib 
with  branches  from  either  side.  In  the  Synaptse,  as  in  all  the 
Holothurians,  the  madreporic  body  is  placed  near  the  mouth, 
between  two  of  the  ambulacra,  and  opposite  the  fifth  or  odd  one. 
The  tube,  connecting  with  the  central  tube  around  the  mouth, 
by  means  of  which  it  communicates  with  the  ambulacral  tubes, 
is  very  short. 

Caudina.    (Cawlina  arenata  STIMPS.) 

Several  other  Holothurians  are  frequently  met  with  on  our 
shores.  Among  them  is  the  Caudina  arenata  (Fig.  126),  a 
small  Holothurian,  yellowish  in  color,  and  thick  in  texture, 

Fig.  126. 


by  no  means  so  pretty  as  the  white  transparent  Synapta  ;  the 
tentacles  are  short,  resembling  a  crown  of  cloves  around  the 
mouth.  It  lives  in  the  sand,  and  may  be  found  in  great  numbers 
on  the  sandy  beaches  after  a  storm. 


Fig.  126.    Caudina  arenata  ;  natural  size. 


13 


98  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

Cuvieria.    (Cuvieria  squamata  D.  &  K.) 

The  Holotlmrian  of  our  coast,  excelling  all  the  rest  in  beauty, 
is  the  Cuvieria.  (Fig.  127.)  As  it  lies  011  the  sand,  a  solid  red 
lump,  with  neither  grace  of  form  nor  beauty  of  color,  even  the 
vividness  of  its  tint  growing  dull  and  dead  when  it  is  removed 
from  its  native  element,  certainly  no  one  could  suspect  that  it 
possessed  any  hidden  charm ;  but  place  it  in  a  glass  bowl  with 
fresh  sea-water  ;  the  dull  red  changes  to  deep  vivid  crimson,  the 
tentacles  creep  out  (Fig.  127)  softly,  and  slowly,  till  the  mouth 

Fig.  127. 


is  surrounded  by  a  spreading  wreath,  comparable  for  richness  of 
tint,  and  for  delicate  tracery,  to  the  most  beautiful  sea-weeds. 
These  tentacles,  when  fully  expanded,  are  as  long  as  the  body  it 
self.  A  limestone  pavement  composed  of  numerous  pieces  covers 
almost  the  whole  surface  of  the  animal ;  this  apparatus  cor 
responds,  as  we  have  already  mentioned,  to  the  warts  containing 
anchors  in  the  Synapta  ;  but  in  the  latter,  the  limestone  parti 
cles  are  smaller,  whereas  in  the  Cuvieria  they  are  developed  to 
a  remarkable  extent.  This  animal  is  very  sluggish,  the  ambula- 
cral  suckers,  found  only  on  three  of  the  tubes,  being  arranged 
in  such  a  way  as  to  form  a  sort  of  sole  on  which  they  creep ; 

Fig.  127.     Cuvieria  ;  natural  size. 


PENTACTA. 


99 


the  sole  is  tough  and  leathery  in  texture,  but  free  from  the 
limestone  pavement  described  above.  The  young  (Figs.  128, 
129)  are  very  common,  swimming  freely  about,  and  more 
readily  found  than  the  adult ;  they  are  of  a  bright  vermilion 
color,  but  the  tentacles  hardly  branch  at  that  age,  nor  is  the 
limestone  pavement  formed,  which  gives  such  a  peculiar  aspect 

Fig.  129. 


Fig.  128. 


to  the  full-grown  animal.  The  young  Cuvieria,  somewhat  older 
than  that  represented  in  Fig.  129,  are  found  in  plenty  under 
stones  at  low-water  mark,  just  after  they  have  given  up  their 
nomadic  habits,  and  when  the  limestone  pavement  begins  to  be 
developed. 

Pentacta.    (Pentacta  frondosa  JAG.) 

The  highest  of  our  Holothurians  in  structure,  is  the  Pentacta. 
(Fig.  130.)  It  is  very  rare  on  our  beaches,  though  occasionally 
found  under  stones  at  low-water  mark  ;  farther  north,  in  Maine, 
and  at  Grand  Manan,  it  is  very  common,  covering  all  the  rocks 
near  low-water  mark.  It  is  a  chocolate  brown  in  color,  and 


Fig.  128.    Young  Cuvieria,  much  enlarged  ;  I  body,  g  tentacles. 

Fig.  129.    Somewhat  older  Cuvieria  ;  I  body,  g  tentacle  round  mouth,  g1  tentacle  of  sole,  b  madre- 
poric  tentacle. 


100  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

measures,  when  fully  expanded,  some  fifteen  to  eighteen  inches 
in  length.  Unlike  the  Cuvieria,  the  ambulacral  suckers  are 
evenly  distributed  and  almost  equally  developed  on  all  the  tubes  ; 
between  the  five  rows  of  ambulacral  suckers  are  scattered  irregu 
larly  certain  appendages  resembling  suckers,  but  found  on  exam 
ination  not  to  be  true  locomotive  suckers,  and  called  on  that 

Fig.  130. 


account  false  ambulacra.  These  are  the  organs  corresponding 
to  the  warts  around  the  mouth  of  the  Synapta.  Although  the 
ambulacral  suckers  are,  as  we  have  said,  equally  developed  on  all 
the  tubes,  yet  the  Pentacta  does  not  use  them  indiscriminately 
as  locomotive  organs.  In  Pentacta,  as  well  as  in  all  Holotlm- 
rians,  whether  provided  with  ambulacral  suckers,  or,  like  the 
Synapta  and  Caudina,  deprived  of  them,  the  odd  ambulacrum, 
viz.  the  one  placed  opposite  the  madreporic  body,  is  always  used 
to  creep  upon,  and  forms  the  under  surface  of  the  animal. 

The  correspondence  between  the  different  phases  of  growth  in 
the  young  Pentacta,  and  the  adult  forms  of  the  orders  described 
above,  the  Synapta,  Caudina,  Cuvieria,  and  Pentacta  itself,  is  a 
striking  instance  of  the  way  in  which  embryonic  forms  illustrate 
the  relative  standing  of  adult  animals.  In  the  earlier  stages  of 
its  development,  the  ambulacral  tubes  alone  are  developed  in  the 
Pentacta  ;  in  this  condition  it  recalls  the  lower  orders  of  Holo- 
thurians,  as  the  Synapta  and  Caudina  ;  then  a  sole  is  formed  by 
the  greater  development  of  three  of  the  ambulacra,  and  in  this 
state  it  reminds  us  of  the  next  in  order,  the  Cuvieria,  while  it  is 

Fig.  130.     Pentacta  frondosa  ;  expanded  about  one  third  the  natural  size. 


ECHINOIDS.  101 

only  in  assuming  its  adult  form  that  the  Pentacta  develops  its 
other  ambulacra,  with  their  many  suckers. 

The  Pentacta  resembles  the  Trepang,  so  highly  valued  by  the 
Chinese  as  an  article  of  food,  and  forms  a  not  unsavory  dish, 
having  somewhat  the  flavor  of  lobster. 


Sea-urchin.    (Toxopneustes  drobachiensis  AG.) 

Sea-urchins  (Fig.  131)  are  found  in  rocky  pools,  hidden  away 
usually  in  cracks  and  holes.  They  like  to  shelter  themselves  in 
secluded  nooks,  and,  not  satisfied  even  with  the  privacy  of  such  a 
retreat,  they  cover  themselves  with  sea-weed,  drawing  it  down 
with  their  tentacles,  and  packing  it  snugly  above  them,  as  if  to 
avoid  observation.  This  habit  makes  them  difficult  to  find,  and 
it  is  only  by  parting  the  sea-weed,  and  prying  into  the  most 
retired  corners  in  such  a  pool,  that  one  detects  them.  Their 
motions  are  slow,  and  they  are  less  active  than  either  the  Star 
fish  or  the  Ophiuran,  to  both  of  which  they  are  so  closely  allied. 

Let  us  look  at  one  first,  as  seen  from  above,  with  all  its  various 
organs  fully  extended.  (Fig.  131.)  The  surface  of  the  animal  is 
divided  by  ten  zones,  like  ribs  on  a  melon,  only  that  these  zones 
differ  in  size,  five  broad  zones  alternating  with  five  narrower  ones. 
The  broad  zones,  representing  the  interambulacral  system,  are 
composed  of  large  plates,  supporting  a  number  of  hard  projecting 
spines,  while  the  narrow  zones,  forming  the  ambulacral  system, 
are  pierced  with  small  holes,  arranged  in  regular  rows,  (Fig.  132,) 
through  which  extend  the  tentacles  terminating  with  little  cups 
or  suckers.  These  zones  converge  towards  the  summit  of  the  ani 
mal,  meeting  in  the  small  area  which  here  represents  the  dorsal 
system ;  this  area  is  filled  by  ten  plates,  five  larger  ones  at  the 
extremity  of  the  interambulacral  zones,  and  five  smaller  ones  at 
the  extremity  of  the  ambulacral  zones.  (Fig.  132.)  In  the  five 
larger  plates  are  the  ovarian  openings,  so  called  because  each 


102 


MARINE   ANIMALS    OF    MASSACHUSETTS    BAY. 


one  is  pierced  by  a  small  hole  through  which  the  eggs  are 
passed  out,  while  in  the  five  smaller  plates  are  the  eye-specks. 
The  ovaries  themselves  consist  of  long  pouches  or  sacs,  carried 
along  the  inner  side  of  each  ambulacrum  ;  one  of  these  ovarian 
plates  is  larger  than  the  others,  and  forms  the  madreporic  body, 

?ig.  131. 


being  pierced  with  many  minute  holes  ;  here,  as  in  the  Star-fish, 
it  is  placed  between  two  of  the  ambulacral  rows,  and  opposite  the 
fifth  or  odd  one.  Looked  at  from  the  under  or  the  oral  side,  as 
seen  in  Fig.  184,  the  animal  presents  the  mouth,  a  circular  aper 
ture  furnished  with  five  teeth  in  its  centre  ;  these  five  teeth  open- 
rig.  131.  Toxopneustes  from  above,  with  all  the  appendages  expanded  ;  natural  size. 


SEA-URCHIN. 


103 


ing  into  a  complicated  intestine  to  be  presently  described.  From 
the  month,  the  ten  zones  diverge,  curving  upward  to  meet  in  the 
dorsal  area  on  the  summit  of  the  body.  (Fig.  133.) 

Fig.  132.  Fig.  133. 


£  r--b  \  '  ^^sps&desss 

liilSliiPi 

l^ifil^ 

"fejfts^ 

Let  us  now  examine  the  appearance  and  functions  of  the  various 
appendages  on  the  surface.  The  tentacles  have  a  variety  of  func 
tions  to  perform  ;  they  are  the  locomotive  appendages,  and  for 
this  reason,  as  we  have  seen,  the  zones  along  which  they  are  placed 
are  called  the  ambulacra,  while  the  intervening  spaces,  or  the 
broad  zones,  are  called  the  interambulacra.  It  should  not  be  sup 
posed,  however,  that  the  locomotive  appendages  are  the  only  ones 
to  be  found  on  the  ambulacra,  for  spines  occur  011  the  narrow  as 
well  as  on  the  broad  ones,  though  the  larger  and  more  prominent 
ones  are  always  placed  on  the  latter.  The  tentacles  are  also 
subservient  to  circulation,  for  the  water  which  is  taken  in  at  the. 
madreporic  body  passes  into  all  the  tentacles,  sometimes  called  on 
that  account  water-tubes.  Beside  these  offices  the  tentacles  are 
constantly  busy  catching  any  small  prey,  and  conveying  it  to 
the  mouth,  or  securing  the  bits  of  sea-weed  with  which,  as  has 
been  said,  these  animals  conceal  themselves  from  observation. 
It  is  curious  to  see  their  fine  transparent  feelers,  fastening  them 
selves  by  means  of  the  terminal  suckers  on  such  a  floating  piece 
of  sea-weed,  drawing  it  gently  down  and  packing  it  delicately 
over  the  surface  of  the  body.  As  locomotive  appendages,  the  ten 
tacles  are  chiefly  serviceable  on  the  lower  or  oral  side  of  the  ani 
mal,  which  always  moves  with  the  mouth  downward.  About  this 
portion  of  the  body  the  tentacles  are  numerous  (Fig.  134)  and 
large,  and  when  the  animal  advances  it  stretches  them  in  a  given 


Fig.  132.     Portion  of  shell  of  Fig.  131,  with  spines  rubbed  off.     (Ayassiz.) 
Fig.  133.     Sea-urchiu  shell  with  all  the  spines  removed.  (Agassiz.) 


104 


MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 


direction,  fastens  them  by  means  of  the  suckers  on  some  surface, 
be  it  of  rock,  or  shell,  or  the  side  of  the  glass  jar  in  which  they 
are  kept,  and  being  thus  anchored  it  drags  itself  forward.  The 
tentacles  are  of  a  violet  hue,  though  when  stretched  to  their 

Fig.  135. 


Fig.  134. 


greatest  length  they  lose  their  color,  and  become  almost  white 
and  transparent ;  but  in  their  ordinary  condition  the  color  is 
quite  decided,  and  the  rows  along  which  they  occur  make  as 
many  violet  lines  upon  the  surface  of  the  body. 

Almost  the  sole  function  of  the  spines  seems  to  be  that  of  pro 
tecting  the  animal,  and  enabling  it  to  resist  the  attacks  of  its  ene 
mies,  the  force  of  the  waves,  or  any  sudden  violent  contact  with 
the  rocks.  The  spines,  when  magnified,  are  seen  to  be  finely  ribbed 
for  nearly  the  whole  length  (Fig.  135),  the  bare  basal  knob  serv 
ing  as  the  point  of  attachment  for  the  powerful  muscles,  which 
move  these  spines  on  a  regular  ball-and-socket  joint,  the  ball  sur 
mounting  the  tubercles  (seen  in  Fig.  132),  which  fit  exactly  in  a 
socket  at  the  base  of  the  spine.  In  a  transverse  section  of  a  spine 
(Fig.  136),  we  see  that  the  ribs  visible  on  the  outside  are  delicate 

Fig.  134.    Sea-urchin  seen  from  the  mouth  side.  (Agassiz.) 
Fig.  135.     Magnified  spine. 


SEA-URCHIN.  105 

columns  placed  closely  side  by  side,  and  connected  by  transverse 
rods  forming  an  exceedingly  delicate  pattern.  Beside  the  tentacles 
and  the  spines,  they  have  other  external  appendages,  of  which 
the  function  long  remained  a  mystery,  and  is  yet  but  partially 
explained  ;  these  are  the  so-called  pedicellaria3 ;  they  consist  of  a 
stem  (s,  Fig.  137),  which  becomes  swollen  (j?,  Fig.  137)  into  a 

Fig.  136.  Fig.  137. 


thimble-shaped  knob  at  the  end  (£,  Fig.  137)  ;  this  knob  may 
seem  solid  and  compact  at  first  sight,  but  it  is  split  into  three 
wedges,  which  can  be  opened  and  shut  at  will.  When  open, 
these  pedicellariae  may  best  be  compared  to  a  three-pronged  fork, 
except  that  the  prongs  are  arranged  concentrically  instead  of  on 
one  plane,  and,  when  closed,  they  fit  into  one  another  as  neatly 
as  the  pieces  of  a  puzzle. 

If  we  watch  the  Sea-urchin  after  he  has  been  feeding,  we 
shall  learn,  at  least,  one  of  the  offices  which  this  singular 
organ  performs  in  the  general  economy  of  the  animal.  That 
part  of  his  food  which  he  ejects  passes  out  at  an  opening  on  the 
summit  of  the  body,  in  the  small  area  where  all  the  zones  con 
verge.  The  rejected  particle  is  received  on  one  of  these  little 
forks,  which  closes  upon  it  like  a  forceps,  and  it  is  passed  on  from 
one  to  the  other,  down  the  side  of  the  body,  till  it  is  dropped  off 
into  the  water.  Nothing  is  more  curious  and  entertaining  than 
to  watch  the  neatness  and  accuracy  with  which  this  process  is 
performed.  One  may  see  the  rejected  bits  of  food  passing  rapidly 
along  the  lines  upon  which  these  pedicellaria?  occur  in  greatest 
number,  as  if  they  were  so  many  little  roads  for  the  conveying 

Fig.  136.    Transverse  section  of  spine  ;  magnified. 

Fig.  137.     Pedicellaria  of  Sea-urchin  ;  *  stem,  p  base  of  fork,  t  fork. 

14 


106  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

away  of  the  refuse  matters  ;  nor  do  tho  forks  cease  from  their 
labor  till  the  surface  of  the  animal  is  completely  clean,  and  free 
from  any  foreign  substance.  Were  it  not  for  this  apparatus  the 
food  thus  rejected  would  be  entangled  among  the  tentacles  and 
spines,  and  be  stranded  there  till  the  motion  of  the  water  washed 
it  away.  These  curious  little  organs  may  have  some  other  office 
than  this  very  laudable  and  useful  one  of  scavenger,  and  this 
seems  the  more  probable  because  they  occur  over  the  whole  surface 
of  the  body,  while  they  seem  to  pass  the  excrements  only  along 
certain  given  lines.  They  are  especially  numerous  about  the 
mouth,  where  they  certainly  cannot  have  this  function  ;  we  shall 
see  also  that  they  bear  an  important  part  in  the  structure  of  the 
Star-fish,  where  there  are  no  such  avenues  on  the  upper  surface, 
for  the  passage  of  the  refuse  food,  as  occur  on  the  Sea-urchin. 

On  opening  a  Sea-urchin,  we  find  that  the  teeth  (Fig.  138), 
which  seem  at  first  sight  only  like  .five  little  conical  wedges 
around  the  mouth  (Fig.  134),  are  connected 
with  a  complicated  intestine,  which  extends 
spirally  from  the  lower  to  the  upper  floor  of 
the  body,  festooning  itself  from  one  ambula 
cra!  zone  to  the  next,  till  it  reaches  the  sum 
mit,  where  it  opens.  This  intestine  leads  into 
the  centre  of  the  teeth,  the  jaws  themselves, 
which  siistain  the  teeth,  being  made  up  of  a 
number  of  pieces,  and  moved  by  a  complicated 
system  of  musciilar  bands.  When  the  intes 
tine  is  distended  with  food,  it  fills  the  greater  part  of  the  inner 
cavity  ;  the  remaining  space  is  occupied  in  the  breeding  season 
by  the  genital  organs.  In  a  section  of  the  Sea-urchin,  one  may 
also  trace  the  tube  by  which  the  supply  of  water,  first  filtered 
through  the  madreporic  body,  is  conveyed  to  the  ambulacra ;  it 
extends  from  the  summit  of  the  body  to  the  circular  tube  sur 
rounding  the  mouth. 

EchinaracTinius.    (Echinarachnius  parma  GRAY.) 

Beside  the  Toxopneustes  (Fig.  131)  described  above,  we  have 
another    Sea-urchin  very  common   along  our  shores.      Among 

Fig   138.    Teeth  of  Sea-urchin,  so-called  Lantern  of  Aristotle. 


ECHINARACHNIUS.  107 

children  who  live  near  sandy  beaches,  they  are  well  known  as 
"  sand-cakes "  (Fig.  139),  and  indeed  they  are  so  flat  and 
round,  that,  when  dried  and  deprived  of  their  bristles,  they  look 
not  unlike  a  cake  with  a  star-shaped  figure  on  its  surface.  (Fig. 
139.)  When  first  taken  from  the  water  they  are  of  a  dark 
reddish  brown  color,  and  covered  with  small  silky  bristles.  The 

Fig  139. 


disk  is  so  flat,  being  but  very  slightly  convex  on  the  upper  side, 
that  one  would  certainly  not  associate  it  at  first  sight  with  the 
common  spherical  Sea-urchin  or  Sea-egg,  as  the  Toxopneustes  is 
sometimes  called.  But  upon  closer  examination  the  delicate  am- 
bulacral  tubes  or  suckers  may  be  seen  projecting  from  along  the 
line  of  the  ambulacra,  as  in  the  spherical  Sea-urchin  ;  and  though 
these  ambulacra  become  expanded  near  the  summit  into  gill-like 
appendages,  forming  a  sort  of  rosette  in  the  centre  of  the  disk, 
they  are,  nevertheless,  the  same  organs,  only  somewhat  more 
complicated.  When  such  a  disk  is  dried  in  the  sun,  and  the 

Fig.  139.    Echinarachnius,  seen  from  above,  with  the  spines  on  part  of  the  shell  ;  a  ainbulacral  zone, 
i  interambulacral  zone. 


108 


MARINE   ANIMALS    OF    MASSACHUSETTS    BAY. 


Fig.  140. 


bristles  entirely  removed,  the  lines  of  suture  of  the  plates  com 
posing  it,  and  corresponding  exactly  to  those  of  the  spherical 
Sea-urchin,  may  very  readily  be  seen,  (a  and  z,  Fig.  139.) 

This  flat  Sea-urchin  or  Echinarachnius,  as  it  is  called,  belongs 
to  a  group  of  Sea-urchins  known  as  Clypeastroids  (shield-like 
Sea-urchins).  In  a  section  (Fig.  140)  exposing  the  internal 
structure,  one  cannot  but  be  reminded  by  its  general  aspect  of 

an  Aurelia.  Could  one  solidify 
an  Aurelia  it  would  present  much 
the  same  appearance  ;  another  evi 
dence  that  all  the  Radiates  are 
built  on  one  plan,  their  differences 
being  only  so  many  modes  of  ex 
pressing  the  same  structural  idea. 
The  teeth  or  jaws  in  this  flat  Sea- 
urchin  are  not  so  complicated  as  in 
the  Toxopneustes,  being  simply  flat 
pieces,  arranged  around  the  mouth 
(o,  Fig.  140),  without  the  apparatus  of  muscular  bands  by  means 
of  which  the  teeth  are  moved  in  the  other  genus.  It  is  a  curious 
fact,  considered  in  relation  to  the  general  radiate  structure  of 
these  animals,  that  the  teeth,  instead  of  moving  up  and  down  like 
the  jaws  in  Yerte"brates,  or  from  right  to  left  like  those  of  Articu 
lates,  move  concentrically,  all  converging  towards  the  centre. 


STAR-FISHES. 

Star-fish.     (Astracanfliion  berylinus  AG.) 

Although  there  is  the  closest  homology  of  parts  between  the 
Star-fish  and  the  Sea-urchin,  the  arrangement  of  these  parts,  and 
the  external  appearance  of  the  animals,  as  a  whole,  are  entirely 
different.  The  Star-fish  has  zones  corresponding  exactly  to  those 


Fig.  140.    Transverse  section  of  Echinarachnius  ;  o  mouth,  e  e  ambulacra,  c  m  atnbulacral  ramifica 
tions,  ww  interambulacra.  (Jlyassiz) 


STAR-FISH. 


109 


of  the  Sea-urchin,  but  instead  of  being  drawn  together,  and  united 
at  the  summit  of  the  animal,  so  as  to  form  a  spherical  outline, 
they  are  spread  out  on  one  level  in  the  shape  of  a  star.  This 
change  in  the  general  arrangement  brings  the  eye-specks  to  the 
extremities  of  the  arms,  and  places  the  ovarian  openings  in  the 
angles  between  the  arms.  The  madreporic  body  is  situated  on 
the  upper  surface  of  the  disk  (Fig.  142),  at  the  angle  between 
two  of  the  arms,  and  consequently  between  two  of  the  ambulacra, 
and  opposite  the  odd  one.  The  tube  into  which  it  opens,  runs 
vertically  from  the  upper  floor  of  the  disk  to  the  lower,  where  it 
connects  with  the  circular  tube  around  the  mouth,  and  thus  com 
municates  with  all  the  ambulacral  rows.  The  ambulacral  zones 
which,  in  the  Star-fish,  have  the  shape  of  a  furrow,  run  along  the 
lower  side  of  each  ray  (Fig.  141)  ;  the  interambulacral  zones 
are  divided,  their  plates  being  arranged  in  rows  along  either  side 
of  the  ambulacral  furrows.  The  ambulacral  furrow,  like  the 
ambulacral  zone  in  the  Sea-urchin,  is  pierced  with  numerous 
holes,  alternating  with  each  other  in  a  kind  of  zigzag  arrange 
ment,  one  hole  a  little  in  advance,  the  next  a  little  farther  back, 
and  so  on,  and  through  these  holes  pass  the  tenta 
cles,  terminating  in  suckers,  as  in  the  Sea-urchins, 
and  serving  as  in  them  for  locomotive  organs.  The 
most  prominent  and  strongest  spines  are  arranged 
upon  the  large  interambulacral  plates  on  both  sides 
of  the  ambulacral  furrows  ;  but  the  upper  surface  of 
the  animal  is  also  completely  studded  with  smaller 
spines,  scattered  at  various  distances,  apparently 
without  any  regular  arrangement.  (Fig.  142.) 

The  position  of  the  pedicellarias  is  quite  dif 
ferent  from  that  which  they  occupy  in  the  Sea- 
urchin,  where  they  are  scattered  singly  between 
the  spines  and  tentacles,  though  more  'regularly 
and  closely  grouped  along  the  lines  upon  which  the  refuse  food 
is  moved  off.  In  the  Star-fish,  on  the  contrary,  these  singular 
organs  seem  to  be  grouped  for  some  special  purpose  around  the 
spines,  on  the  upper  surface  of  the  body.  Every  such  spine 
swells  near  its  point  of  attachment,  thus  forming  a  spreading  base 

Fig.  141.     Star-fish  ray,  seen  from  mouth  side. 


110  MARINE    ANIMALS    OF   MASSACHUSETTS    BAY. 

(Fig.  143),  around  which  the  pedicellariae  are  arranged  in  a  close 
wreath,  in  the  centre  of  which  the  summit  of  the  spine  projects  ; 
they  differ  also  from  those  of  the  Sea-urchin  in  having  two 
prongs  instead  of  throe.  Other  pedicellariae  are  scattered  inde 
pendently  over  the  surface  of  the  animal,  but  they  are  smaller 

Fig.  142. 


than  those  forming  the  clusters  and  connected  with  the  spines. 
The  function  of  these  organs  in  the  Star-fish  remains  unexplained  ; 
the  opening  on  the  upper  surface,  through  which  the  refuse  food 
is  thrown  out,  is  in  such  a  position  that  they  evidently  do  not 
serve  here  the  same  purpose  which  renders  them  so  useful  to  the 
Sea-urchin.  Occasionally  they  may  be  seen  to  catch  small  prey 

Fig.  142     Star-fish  ;  natural  size,  seen  from  above. 


STAR-FISH.  Ill 

with  these  forks,  little  Crustacea,  for  instance  ;  but  this  is  prob 
ably  not  their  only  office.  The  Star-fish  has  a  fourth  set  of 
external  appendages  in  the  shape  of  little  water-tubes.  (Seen  in 
Fig.  143.)  The  upper  surface  of  the  back  consists  of  a  strong 
limestone  network  (Fig.  144),  and  certain  openings  in  this  net 
work  are  covered  with  a  thin  membrane  through  which  these 
water-tubes  project.  It  is  supposed  that  water  may  be  intro 
duced  into  the  body  through  these  tubes  ;  but  while  there  can  be 

Fig.  144. 


no  doubt  that  they  are  constantly  filled  with  water,  and  are 
therefore  directly  connected  with  the  circulation  through  the 
madreporic  body  (Fig.  145),  no  external  opening  has  as  yet  been 
detected  in  them.  The  fact,  however,  that  when  these  animals 
are  taken  out  of  their  native  element,  the  water  pours  out  of  them 
all  over  the  surface  of  the  back,  so  that  they  at  once  collapse  and 
lose  entirely  their  fulness  of  outline,  seems  to  show  that  water 
does  issue  from  those  tubes.  The  ends  of  the  arms  are  always 
slightly  turned  up,  and  at  the  summit  of  each  is  a  red  eye-speck. 
The  tentacles  about  the  eye  become  very 
delicate  and  are  destitute  of  suckers. 

These  animals  have  a  singular  mode  of 
eating  ;  they  place  themselves  over  what 
ever  they  mean  to  feed  upon,  as  a  cockle 
shell  for  instance,  the  back  gradually 
rising  as  they  arch  themselves  above  it ; 
they  then  turn  the  digestive  sac  or  stom 
ach  inside  out,  so  as  to  enclose  their  prey 

Fig.  143.    Single  spine  of  Star-fish,  with  surrounding  appendages  ;  magnified. 
Fi«r.  144.     Limestone  network  of  hack  of  Star-fish. 
Fig   145.     Madreporic  body  of  Star-fish  ;  magnified. 


112 


MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 


completely,  and  proceed  leisurely  to  suck  out  the  animal  from  its 
shell.  Cutting  open  any  one  of  the  arms  we  may  see  the  yellow 
folds  of  the  stomach  pouches  which  extend  into  each  ray ;  within 
the  arms,  extending  along  either  side  of  the  upper  surface,  are 
also  seen  the  ovaries,  like  clusters  of  small  yellow  berries.  Im 
mediately  below  these,  along  the  centre  of  the  lower  floor  of  each 
ray,  runs  the  ridge  formed  by  the  ambulacral  furrow,  and  upon 
either  side  of  this  ridge  are  placod  the  vesicles,  by  means  of 
which  the  tentacles  may  be  filled  and  emptied  at  the  will  of  the 
animal ;  the  rest  of  the  cavity  of  the  ray  is  filled  by  the  liver. 
The  mouth,  which  is  surrounded  by  a  circular  tube,  is  not  fur 
nished  with  teeth,  as  in  the  Sea-urchin  ;  but  the  end  of  each 
ambulacral  ridge  is  hard,  thus  serving  the  purpose  of  teeth. 


Fig  146. 


Cribrella.    (Cribrella  oculata  FORBES.) 

Our  coast,  as  we  have  said,  is  not  rich  in  the  variety  of  Star 
fishes.  We  have  two  large  species,  one  of  a  dark-brown 
color  (Fig.  132),  the  Astracanthion  berylinus,  and  the  other, 
the  A.  pallidus,  of  a  pinkish  tint ;  then  there  is  the  small  Cri 
brella,  inferior  in  structural  rank  to  the  two  above  mentioned. 
(Fig.  146.)  This  pretty  little  Star-fish  presents  the  greatest 

variety  of  colors ;  some  are 
dyed  in  Tyrian  purple,  others 
have  a  paler  shade  of  the  same 
hue,  some  are  vermilion,  others 
a  bright  orange  or  yellow.  A 
glass  dish  filled  with  Cribrellas 
might  vie  with  a  tulip-bed  in 
gayety  and  vividness  of  tints. 
The  disk  of  the  Cribrella  is 
smooth,  instead  of  being  cov 
ered,  like  the  larger  Star-fishes, 
with  a  variety  of  prominent  ap 
pendages.  The  spines  are  ex 
ceedingly  short,  crowded  like 
little  warts  over  the  surface.  It  is  an  interesting  fact,  illustrat- 


Fig.  146.     Cribrella  from  above  5  natural  size. 


CTENODISCUS.  113 

ing  again  the  correspondence  between  the  adult  forms  of  the 
lower  orders  and  the  phases  of  growth  in  the  higher  ones, 
that  these  spines  have  an  embryonic  character.  One  would 
naturally  expect  to  find  that  these  small  spines  of  the  adult  Cri- 
brella  would  differ  from  those  of  the  other  full-grown  Star-fishes 
chiefly  in  size,  that  they  would  bo  a  somewhat  modified  pattern 
of  the  same  thing  on  a  smaller  scale  ;  but  when  examined  under 
the  microscope,  they  resemble  the  spines  of  the  higher  orders  in 
their  embryonic  condition  ;  it  is  not,  in  fact,  a  difference  in  size 
merely,  but  a  difference  in  degree  of  development.  The  Cri- 
brella  moves  usually  with  two  of  the  arms  turned  backward,  and 
the  three  others  advanced  together,  the  two  posterior  ones  being 
sometimes  brought  so  close  to  each  other  as  to  touch  for  their 
whole  length. 

Hipp  aster  id.     (Hippasteria  phrygiana  AG.) 

Beside  these  Star-fishes  we  have  the  pentagonal  Hippasteria 
(Hippasteria  phrygiana  AG.),  like  a  red  star  with  rounded  points, 
found  chiefly  in  deep  water,  though  it  is  occasionally  thrown  up 
on  the  beaches.  It  has  but  two  rows  of  large  tentacles,  termi 
nating  in  a  powerful  sucking  disk.  The  pedicellariae  on  this 
Star-fish  resemble  large  two-pronged  clasps,  arranged  principally 
along  the  lower  side.  The  pentagonal  Star-fishes  of  our  coast 
are  in  striking  contrast  to  the  long-armed  species  we  have  just 
described  ;  they  are  edged  with  rows  of  large  smooth  plates,  and 
do  not  possess  the  many  prominent  spines  so  characteristic  of 
the  ordinary  Star-fishes. 

CtenodlSCUS.     (Ctenodiscus  crispatus  T>.  &  K.) 

The  Ctenodiscus  {Ctenodiscus  crispatus  D.  &  K.,  Fig.  147),  an 
inhabitant  of  more  northern  waters,  but  seeming  also  to  be  at 
home  here  occasionally,  is  another  pentagonal  Star-fish.  It  lives 
in  deep  water,  and  frequents  muddy  bottoms.  The  peculiar 
structure  of  their  ambulacra  has  probably  some  reference  to  this 
mode  of  living,  for  they  are  entirely  wanting  in  the  sucking  disks 
so  characteristic  of  the  other  members  of  this  class,  and  their 

15 


114  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

tentacles  are  pointed, 
as  if  to  enable  them 
to  work  their  way 
through  the  mud  in 
which  they  make  their 
home.  The  pointed 
tentacles  of  this  genus 
are  characteristic  of  a 
large  group  of  Star 
fishes,  and  it  is  an  im 
portant  fact,  as  show 
ing  their  lower  stand 
ing,  that  this  feature, 
as  well  as  the  pentag 
onal  outline,  obtains 
in  the  earlier  stages 

of  growth  of  our  more  common  Star-fishes,  while  in  their  adult 
condition  they  assume  the  deeply  indented  star-shaped  outline, 
and  have  suckers  at  the  extremities  of  the  tentacles. 

Solaster.    (Solaster  endeca  FORBES.) 

We  find  also  among  Star-fishes  the  same  tendency  to  multipli 
cation  of  parts  so  common  among  the  Polyps  and  Acalephs. 
Our  Solaster  {Solaster  endeca  Forbes),  for  instance,  has  no  less 
than  twelve  arms  ;  it  inhabits  more  northern  latitudes,  though 
sometimes  found  in  our  Bay  ;  on  the  coast  of  Maine  it  is  quite 
common,  and  occurs  in  company  with  another  many-rayed  spe 
cies,  the  Crossaster  papposa  M.  &  T.  The  color  of  both  of  these 
Star-fishes  is  exceedingly  varied  ;  we  find  in  the  Solaster  as  many 
different  hues  as  in  the  Cribrella,  which  it  resembles  in  the  struc 
ture  of  its  spines,  while  in  the  Crossaster  bands  of  different  tints 
of  red  and  purple  are  arranged  concentrically,  and  the  whole  sur 
face  of  the  back  is  spotted  with  brilliantly-tinged  tiny  wreaths  of 
water-tubes,  crowded  round  the  base  of  the  different  spines,  which 
are  somewhat  similar  to  those  of  the  Astracanthion. 

Fig.  147.     Ctenodiscus,  seen  from  above  :  natural  size. 


OPHIOPHOLIS. 


OPHIURANS. 


Ophiopholis.    (Ophiopholis  belli*  LYM.) 


There  are  but  two  species  of  the  ordinary  forms  of  Ophiurans 
in  Massachusetts  Bay  ;  the  white  Amphiura  {Amphiura  squamata 
Sars),  with  long  slender  arms,  and  the  spotted  Ophiopholis  (Fig. 
148),  with  shorter  and  stouter  arms,  and  in  which  the  disk  is  less 
compact  than  in  the  Amphiura,  and  not  so  perfectly  circular. 

Fig.  148. 


All  Ophiurans  are  difficult  to  find,  from  their  exceeding  shyness  ; 
they  hide  themselves  in  the  darkest  crevices,  and  though  no  eye- 
specks  have  yet  been  detected  in  them,  they  must  have  some 
quick  perception  of  coming  danger,  for  at  the  gentlest  approach 
they  instantly  draw  away  and  shelter  themselves  in  their  snug 
retreats. 

Fig.  148.     Ophiopholis,  from  above  ;  natural  size. 


116  MARINE  ANIMALS    OF    MASSACHUSETTS    BAY. 

They  differ  from  the  Star-fishes  in  having  the  disk  entirely 
distinct  from  the  arms  ;  that  is,  the  arms,  instead  of  merging 
gradually  into  the  disk,  start  at  once  from  its  margin.  They 
have  no  interambulacral  spaces  or  plates ;  but  the  whole  upper 
surface  is  formed  of  large  hard  plates,  which  extend  from  the 
back  over  the  sides  of  the  arms  to  their  lower  surface,  where 
they  form  a  straight  ridge  along  the  centre.  (Fig.  149.)  The  sides 
of  these  plates  are  pierced  with  holes,  through  which  the  ten 
tacles  pass  ;  these  have  not,  like  those  of  the  Star-fishes  and 
Sea-urchins,  a  sucker  at  the  extremity,  biit  are  covered  with  little 
warts  or  tubercles  (Fig.  150)  ;  they  are  their  locomotive  ap- 


Fig.  150. 


pendages,  arid  their  way  of  moving  is  curious  ;  they  first  extend 
one  of  the  arms  in  the  direction  in  which  they  mean  to  move, 
then,  bring  forward  two  others  to  meet  them,  three  arms  being 
thus  usually  in  advance,  and  then  they  drag  the  rest  of  the  body 
on.  They  move  with  much  more  rapidity,  and  seem  more  active, 
than  the  Star-fishes  ;  probably  owing  to  the  greater  independence 
of  the  arms  from  the  disk.  The  spines  project  along  the  mar 
gin  of  the  arms,  and  not  over  the  whole  surface,  the  back  of  the 
arms  being  perfectly  free  from  any  appendages,  and  presenting 
only  the  surface  of  the  plates.  The  madreporic  body  is  formed 
by  a  plate  on  the  lower  side  of  the  disk,  in  a  position  correspond- 

Fig  149.     One  arm  of  Fig.  148  ;  from  the  mouth  side. 
Fig.  150.     Ambulacral  tentacle  of  Ophiopholis  ;  magniaed. 


ASTROPHYTON.  117 

ing  to  that  which  it  occupies  in  the  young  Star-fish  ;  this  plate 
is  one  of  the  large  circular  shields  occupying  the  interambulacral 
spaces  around  the  mouth.  (Fig.  149.)  On  each  side  of  the  arms, 
where  they  join  the  disk,  are  slits  opening  into  the  ovarian  pouches. 
They  have  no  teeth  ;  but  the  hard  ridge  at  the  oral  end  of  the 
ambulacra,  extending  toward  the  mouth  in  Star-fish,  is  still  more 
distinct  and  sharper  in  the  Ophiurans,  approaching  more  nearly 
the  character  of  teeth. 

Astrophyton.    (Astrophyton  Agassizii  STIMP.) 

A  singular  species  of  Ophiuran,  known  among  fishermen  as  the 
"  Basket-fish,"  (Fig.  151,)  is  to  be  found  in  Massachusetts  Bay. 
Its  arms  are  very  long  in  comparison  to  the  size  of  the  disk,  and 
divide  into  a  vast  number  of  branches.  In  moving,  the  animal 
lifts  itself  on  the  extreme  end  of  these  branches,  standing  as  it 
were  on  tiptoe  (Fig.  151),  so  that  the  ramifications  of  the  arms 
form  a  kind  of  trellis-work  all  around  it,  reaching  to  the  ground, 
while  the  disk  forms  a  roof.  In  this  living  house  with  latticed 
walls  small  fishes  and  other  animals  are  occasionally  seen  to  take 
shelter  ;  but  woe  to  the  little  shrimp  or  fish  who  seeks  a  refuge 
there,  if  he  be  of  such  a  size  as  to  offer  his  host  a  tempting  mouth 
ful  ;  he  will  fare  as  did  the  fly  who  accepted  the  invitation  of 
the  spider.  These  animals  are  exceedingly  voracious,  and  some 
times,  in  their  greediness  for  food,  entangle  themselves  in  fishing- 
lines  or  nets.  When  disturbed,  they  coil  their  arms  closely  around 
the  mouth,  assuming  at  such  times  a  kind  of  basket-shape,  from 
which  they  derive  their  name. 

This  Basket-fish  is  honorably  connected  with  our  early  colonial 
history,  being  thought  worthy,  by  no  less  a  personage  than  John 
Winthrop,  Governor  of  Connecticut,  who,  as  he  says,  "  had  never 
seen  the  like,"  to  be  sent  with  "  other  natural  curiosities  of  these 
parts  "  to  the  Royal  Society  of  London,  in  1670.  He  accom 
panies  the  specimen  with  a  minute  description,  omitting  "  other 
particulars,  that  we  may  reflect  a  little  upon  this  elaborate  piece 
of  nature."  His  account  is  as  graphic  as  it  is  accurate,  and  we 
can  hardly  give  a  better  idea  of  the  animal  than  by  extracting 
some  portions  of  it.  "  This  Fish,"  he  says,  "  spreads  itself  from 


118  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY 


Fig.  151. 


Fig.  151.     Astrophyton,  Basket-fish  ;  in  a  natural  attitude. 


ASTROPHYTON.  119 

a  Pentagonal  Root,  which  incompasseth  the  Mouth  (being  in  the 
middle),  into  5  main  Limbs  or  branches,  each  of  which,  just  at 
issuing  out  from  the  Body,  subdivides  itself  into  two,  and  each  of 
these  10  branches  do  again  divide  into  two  parts,  making  20  lesser 
branches  ;  each  of  which  again  divide  into  two  smaller  branches, 
making  in  all  40.  These  again  into  80,  and  these  into  160  ;  and 
these  into  320  ;  these  into  640  ;  into  1280  ;  into  2560  ;  into  5120  ; 
into  10,240  ;  into  20,480  ;  into  40,960 ;  into  81,920  ;  beyond 
which  the  further  expanding  of  the  Fish  could  not  be  certainly 
trac'd";  —  a  statement  which  we  readily  believe,  wondering  only 
at  the  patience  which  followed  this  labyrinth  so  far. 

In  a  later  letter,  after  having  had  an  interview  with  the  fisher 
man  who  caught  the  specimen,  and,  as  he  says,  "  asked  all  the 
questions  I  could  think  needful  concerning  it,"  the  Governor  pro 
ceeds  to  tell  us  that  it  was  caught  "  not  far  from  the  Shoals  of 
Nantucket  (which  is  an  Island  upon  the  Coast  of  New  England)," 
and  that  when  "  first  pull'd  out  of  the  water  it  was  like  a  basket, 
and  had  gathered  itself  round  like  a  Wicker-basket,  having  taken 
fast  hold  upon  that  bait  on  the  hook  which  he  "  (the  fisherman) 
"  had  sunk  down  to  the  bottom  to  catch  other  Fish,  and  having 
held  that  within  the  surrounding  brachia  would  not  let  it  go, 
though  drawn  up  into  the  Vessel ;  until,  by  lying  a  while  on  the 
Deck,  it  felt  the  want  of  its  natural  Element ;  and  then  voluntarily 
it  extended  itself  into  the  flat  round  form,  in  which  it  appear 'd 
when  present'd  to  your  view."  The  Governor  goes  on  to  reflect 
in  a  philosophical  vein  upon  the  purpose  involved  in  all  this  com 
plicated  machinery.  "  The  only  use,"  he  says,  "  that  could  be 
discerned  of  all  that  curious  composure  wherewith  nature  had 
adorned  it  seems  to  be  to  make  it  as  a  purse-net  to  catch  some 
other  fish,  or  any  other  thing  fit  for  its  food,  and  as  a  basket  of 
store  to  keep  some  of  it  for  future  supply,  or  as  a  receptacle  to 
preserve  and  defend  the  young  ones  of  the  same  kind  from  fish 
of  prey  ;  if  not  to  feed  on  them  also  (which  appears  probable 
the  one  or  the  other),  for  that  sometimes  there  were  found  pieces 
of  Mackerel  within  that  concave.  And  he,  the  Fisherman,  told 
me  that  once  he  caught  one,  which  had  within  the  hollow  of  its 
embracements  a  very  small  fish  of  the  same  kind,  together  with 
some  piece  or  pieces  of  another  fish,  which  was  judged  to  be  of  a 


120  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

Mackerel.  And  that  small  one  ('t  is  like)  was  kept  either  for  its 
preservation  or  for  food  to  the  greater  ;  but,  being  alive,  it  seems 
most  likely  it  was  there  lodged  for  safety,  except  it  were  acci 
dentally  drawn  within  the  net,  together  with  that  piece  of  fish 
upon  which  it  might  be  then  feeding."  The  account  concludes 
by  saying,  "  This  Fisherman  could  not  tell  me  of  any  name  it 
hath,  and  't  is  in  all  likelihood  yet  nameless,  being  not  commonly 
known  as  other  Fish  are.  But  until  a  fitter  English  name  be 
found  for  it,  why  may  it  not  bo  called  (in  regard  of  what  hath 
been  before  mentioned  of  it)  a  Basket-Fish,  or  a  Net-Fixh,  or  a 
Purs-net-Fish?"  And  so  it  remains  to  this  day  as  the  Governor 
of  Connecticut  first  christened  it,  the  Basket-fish. 


CRINOIDS. 

The  Crinoids  are  very  scantily  represented  in  the  present  crea 
tion.  They  had  their  day  in  the  earlier  geological  epochs,  when 
for  some  time  they  remained  the  sole  representatives  of  their  class, 
and  were  then  so  numerous  that  the  class  of  Echinoderms,  with 
only  one  order,  seemed  as  full  and  various  as  it  now  does  with 
five.  The  different  forms  they  assumed  in  the  successive  geo 
logical  periods  are  particularly  instructive  ;  these  older  Crinoids 
combined  characters  which  foreshadowed  the  advent  of  the  Oplii- 
urans,  the  true  Star-fishes,  and  the  Sea-urchins  ;  and  so  promi 
nently  were  their  prophetic  characters  developed,  that  mUny  of 
them  are  readily  mistaken  for  Star-fishes  or  Sea-urchins. 

In  later  times  the  group  of  Crinoids  has  been  gradually 
dwindling  in  number  and  variety.  Its  present  representatives 
are  the  Pentacrinus  of  Porto  Rico,  attached  throughout  life  to  a 
stem,  and  the  Comatula,  which  has  a  stem  only  in  the  early 
stages  of  its  growth,  but  is  free  when  adult.  The  Pentacrinus 
bears  the  closer  relation  to  the  more  ancient  Crinoids  (Fig.  152), 
which  were  always  supported  on  a  stem,  while  it  is  only  in  more 


COMATULA. 


321 


recent  periods  that  we  find  the  free  Crinoids,  corresponding  to 
the  Comatula. 


Comatula.    (Alecto  meridionalis  AG.) 

One  large  species  of  Comatula  (Alecto  Eschrichtii  M.  &  T.) 
is  known  on  our  coast,  off  the  shores  of  Greenland,  wher6  it 
has  been  dredged  at  a  depth  of  about  one  hundred  and  fifty 
fathoms,  and  young  specimens  of  the  same  species  have 
been  found  as  far  south  as  Eastport,  Maine.  The  species 
selected  for  representation  here,  however,  (Fig.  153,)  is  one 
quite  abundant  along  the  shores  of  South  Carolina.  It  is  intro 
duced  instead  of  the  northern  one,  because  the  latter  is  so  rare 
that  it  is  not  likely  to  fall  into  the  hands  of  our  readers.  The 
annexed  drawing  (Fig.  154,  magnified  from  Fig.  153)  repre 
sents  a  group  of  the  young  of  the  Charleston  Comatula,  still  at 
tached  to  the  parent  body  by  their  stems,  and  in  various  stages  of 

Fig.  152.    Foesil  Pentacrinus. 


122 


MARINE   ANIMALS    OF    MASSACHUSETTS    BAY. 


development.     At  first  sight,  the  Comatula,  or,  as  it  is  sometimes 

called,  the  feather- 
star,  resembles  an 
Ophiuran  ;  but  on 
a  closer  examination 
we  find  that  the  arms 
are  made  up  of  short 
joints  ;  and  along  the 
sides  of  the  arms,  at 
tached  to  each  joint, 
are  appendages  re 
sembling  somewhat 
the  beards  of  a  feath 
er,  and  giving  to  each 
ray  the  appearance 
of  a  plume  ;  hence 
the  name  of  feather- 
star.  On  one  side 
the  arms  are  covered 
with  a  tough  skin, 
through  which  pro 
ject  the  ambulacra, 
and  on  the  same  side 
of  the  disk  are  situ 
ated  the  mouth  and 
the  anus  ;  the  latter 
projects  in  a  trum 
pet-shaped  proboscis. 
On  the  opposite  side 
of  the  disk  the  Co 
matula  is  covered 
with  plates,  arranged 
regularly  around  a 
central  plate,  which 
is  itself  covered  with 
long  cirri. 

Fig.  153.    Comatula  (Living  Crinoid)  seen  from  the  back  ;  y  group  of  young  Comatulaa  attached  to 
parent. 
Fig.  154.    Magnified  view  of  the  group  of  young  Comatulae  of  Fig.  153. 


EMBRYOLOGY    OF    ECHINODERMS.  123 

We  are  indebted  to  Thompson  for  the  explanation  of  the  true 
relations  of  the  young  Comatula  to  the  present  Pentacrinus  and 
the  fossil  Crinoids.  Supposing  these  young  to  be  full-grown 
animals,  he  at  first  described  them  as  living  representatives  of 
the  genus  Pentacrinus  ;  it  was  only  after  he  had  watched  their 
development,  and  ascertained  by  actual  observation  that  they 
dropped  from  their  stem,  to  lead  an  independent  life  as  free 
Comatuke,  that  he  fully  understood  their  true  connection  with 
the  past  history  of  their  kind,  as  well  as  with  their  contempora 
ries.  In  Fig.  153,  a  faint  star-like  dot  (y)  may  be  seen  attached 
to  the  side  of  the  disk  by  a  slight  line.  In  Fig.  154,  we  have 
that  minute  dot  as  it  appears  under  the  microscope,  magnified 
many  diameters  ;  when  it  is  seen  to  be  a  cirrus  of  a  Comatula, 
with  three  small,  Pentacrinus-like  animals  growing  upon  it,  in 
different  stages  of  development.  In  the  upper  one,  the  branching 
arms  and  the  disk,  with  its  many  plates,  are  already  formed  ; 
and  though  in  the  figure  the  rays  are  folded  together,  they  are 
free,  and  can  be  opened  at  will.  In  the  larger  of  the  two  lower 
buds,  the  plates  of  the  disk  are  less  perfect,  and  the  arms  are 
straight  and  simple,  without  any  ramifications,  though  they  are 
free  and  movable,  whereas,  in  the  smaller  one,  they  are  folded 
within  the  closed  bud. 


EMBRYOLOGY  OF  ECHINODERMS. 

All  Radiates  have  a  special  mode  of  development,  as  distinct 
for  each  class  as  is  their  adult  condition,  and  in  none  are  the 
stages  of  growth  more  characteristic  than  in  the  Echinoderms. 
In  the  Polyps,  the  division  of  the  body  into  chambers,  so  marked 
a  feature  of  their  ultimate  structure,  takes  place  early  ;  in  the 
Acalephs,  the  tubes  which  traverse  the  body  are  hollowed  out  of 
its  mass  in  the  first  stages  of  the  embryonic  growth,  and  we  shall 
see  that  in  the  Echinoderms  also,  the  distinctive  feature  of  their 
structure,  viz.  the  enclosing  of  the  organs  by  separate  walls, 
early  manifests  itself.  This  peculiarity  gives  to  the  internal 


124  MARINE    ANIMALS    OF   MASSACHUSETTS    BAY. 

structure  of  these  animals  so  individual  a  character,  that  some 
naturalists,  overlooking  the  law  of  radiation,  as  prevalent  in  them 
as  in  any  members  of  this  division,  have  been  inclined  to  separate 
them,  as  a  primary  division  of  the  animal  kingdom,  from  the 
Polyps  and  Acalephs,  in  both  of  which  the  body-wall  furnishes 
the  walls  of  the  different  internal  cavities,  either  by  folding  in 
wardly  in  such  a  manner  as  to  enclose  them,  as  in  the  Polyps, 
or  by  the  cavities  themselves  being  hollowed  out  of  the  general 
mass,  as  in  the  Acalephs. 

Star-fish.    (Astracanthion.) 

The  egg  of  the  Star-fish,  when  first  formed,  is  a  transparent, 
spherical  body,  enclosing  the  germinative  vesicle  and  dot.  (See 
Fig.  155.)  As  soon  as  these  disappear,  the  segmentation  of  the 
yolk  begins  ;  it  divides  first  into  two  portions  (see  Fig.  156), 
then  into  four,  then  into  eight,  and  so  on  ;  but  when  there  are 
no  more  than  eight  bodies  of  segmentation  (see  Fig.  157),  they 

Fig.  155.  Fig.  156.  Fig.  157. 


already  show  a  disposition  to  arrange  themselves  in  a  hollow 
sphere,  enclosing  a  space  within,  and  by  the  time  the  segmenta 
tion  is  completed,  they  form  a  continuous  spherical  shell.  At  this 
time  the  egg,  or,  as  we  will  henceforth  call  it,  the  embryo,  escapes 
and  swims  freely  about.  (See  Fig.  158.)  The  wall  next  begins 
to  thin  out  on  one  side,  while  on  the  opposite  side,  which  by  com 
parison  becomes  somewhat  bulging,  a  depression  is  formed  (ma, 
Fig.  159),  gradually  elongating  into  a  loop  hanging  down  within 
the  little  animal,  and  forming  a  digestive  cavity.  (J,  Fig.  160.) 
At  this  stage  it  much  resembles  a  young  Actinia.  The  loop 
spreads  somewhat  at  its  upper  extremity,  and  at  its  lower  end  is 

Fig.  155.    Egg  of  Star-fish. 

Fig.  156.    Egg  of  Star-fish  in  which  the  yolk  has  been  divided  into  two  segments. 

Fig.  157.    Egg  in  which  there  are  eight  segments  of  the  yolk. 


EMBRYOLOGY    OF    ECUINODERMS. 


125 


an  opening,  which  at  this  period  of  the  animal's  life  serves  a 
double  purpose,  that  of  mouth  and  anus  also,  for  at  this  opening 
it  both  takes  in  and  rejects  its  food.  We  shall  see  that  before 
long  a  true  mouth  is  formed,  after  which  this  first  aperture  takes 
its  place  opposite  the  mouth,  retaining  only  the  function  of  the 
anus.  Presently  from  the  upper  bulging  extremity  of  the  diges- 

Fig.  158.  Fig.  159.  Fig.  160.  Fig.  161. 


tivc  cavity,  two  lappets,  or  little  pouches,  project  (ivw1,  Fig.  101)  ; 
they  shortly  become  completely  separated  from  it,  and  form  two 
distinct  hollow  cavities  (ivw1,  Fig.  102).  Here  begins  the  true 
history  of  the  young  Star-fish,  for  these  two  cavities  will  develop 
into  two  water-tubes,  on  one  of  which  the  back  of  the  Star-fish, 
that  is,  its  upper  surface,  covered  with  spines,  will  be  developed, 

Fig.  162.  Fig.  163.  Fig.  164. 


while  on  the  other,  the  lower  surface,  with  the  suckers  and  tenta 
cles,  will  arise.  At  a  very  early  stage  one  of  these  water-tubes 
(w',  Fig.  163)  connects  with  a  smaller  tube  opening  outwards, 
which  is  hereafter  to  be  the  madreporic  body  (6,  Fig.  163). 
Almost  until  the  end  of  its  growth,  these  two  surfaces,  as  we 

Fig.  158.  Larva  just  hatched  from  egg  ;  a  thickened  pole. 

Fig.  159.  Larva  somewhat  older  than  Fig.  158  ;  ma  depression  at  thickened  pole. 

Fig.  160.  Larva  where  the  depression  has  become  a  digestive  cavity  d,  opening  at  a. 

Fig.  161.  Earlets,  w  w'  (water-tubes),  developed  at  the  extremity  of  the  digestive  cavity  d  ;  m  mouth. 

Fig.  162.  More  advanced  larva  ;  a  d  c  digestive  system,  «  vibratile  chord,  m  mouth. 

Fig.  163.  Profile  view  of  larva;  b  madreporic  opening,  w'  earlet,  ad  digestive  system,  m  mouth, 
V  t>'  vibratile  chord. 

Fig.  164.  Larva  showing  mode  of  formation  of  mouth  m,  by  bending  of  digestive  cavity  o 


126  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

shall  see,  remain  separate,  and  form  an  open  angle  with  one 
another ;  it  is  only  toward  the  end  of  the  development  that  they 
unite,  enclosing  between  them  the  internal  organs,  which  have 
been  built  up  in  the  mean  while. 

At  about  the  same  time  with  the  development  of  these  two 
pouches,  so  important  in  the  animal's  future  history,  the  digestive 
cavity  becomes  slightly  curved,  bending  its  upper  end  sideways 

till  it  meets  the  outer  wall,  and  forms 
a  junction  with  it  (w,  Fig.  164).  At 
this  point,  when  the  juncture  takes 
place,  an  aperture  is  presently  formed, 
which  is  the  true  mouth.  The  diges 
tive  sac,  which  has  thus  far  served  as 
the  only  internal  cavity,  now  contracts 
at  certain  distances,  and  forms  three 
distinct,  though  connected  cavities,  as 
in  Fig.  163  ;  viz.  the  oasophagus  lead 
ing  directly  from  the  mouth  (m)  to  the 
second  cavity  or  stomach  (<2),  which 
opens  in  its  turn  into  the  third  cavity, 

the  alimentary  canal.  Meanwhile  the  water-tubes  have  been 
elongating  till  they  now  surround  the  digestive  cavity,  extending 
on  the  other  side  of  it  beyond  the  mouth,  where  they  unite,  thus 
forming  a  Y-shaped  tube,  narrowing  at  one  extremity,  and  divid 
ing  into  two  branches  toward  the  other  end.  (Fig.  165.) 

On  the  surface  where  the  mouth  is  formed,  and  very  near  it  on 
cither  side,  two  small  arcs  arise,  as  v  in  Fig.  162 ;  these  are  cords 
consisting  entirely  of  vibratile  cilia.  They  are  the  locomotive 
organs  of  the  young  embryo,  and  they  gradually  extend  until 
they  respectively  enclose  nearly  the  whole  of  the  upper  and  lower 
half  of  the  body,  forming  two  large  shields  or  plastrons.  (Figs. 
165,  166.)  The  corners  of  these  shields  project,  slightly  at  first 
(Fig.  165),  but  elongating  more  and  more  until  a  number  of 
arms  are  formed,  stretching  in  various  directions  (Figs.  166, 167), 
and,  by  their  constant  upward  and  downward  play,  moving  the 
embryo  about  in  the  water. 

Fig.  165.     Larva  in  which  arms  are  developing,  lettering  as  before  ;  e'  e"  e'"  e*e5e5  arms,  o  oesoph 
agus. 


EMBRYOLOGY    OF    ECIIINODERMS. 


127 


At  this  stage  of  the  growth  of  the  embryo,  we  have  what  seems 
quite  a  complicated  structure,  and  might  be  taken  for  a  complete 
animal ;  this  is  after  all  but  the  prelude  to  its  true  Star-fish  exist 
ence.  While  these  various  appendages  of  the  embryo  have  been 
forming,  changes  of  another  kind  have  taken  place  ;  on  one  of  the 

Fi?.  Ifid. 


two  water-tubes  above  mentioned  (w')?  a*  tne  en(^  nearest  the  di 
gestive  cavity,  a  number  of  lobes  are  formed  (t,  Fig.  166)  ;  this  is 
the  first  appearance  of  the  tentacles.  In  the  same  region  of  the 
opposite  water-tube  (w)  a  number  of  little  limestone  rods  arise, 
which  eventually  unite  to  form  a  continuous  network  ;  this  is  the 

Fig  166.     Adult  Larva,  so-called  Brachiolaria,  lettering  as  before  ;  r  back  of  young  Star-fish,  t  ten- 
tacl'js  of  young  Star-fish,  //'  brachiolar  appendages. 


128 


MARINE    ANIMALS    OF   MASSACHUSETTS    BAY. 


Fig.  167. 


beginning  of  the  back  of  the  Star-fish  (r,  Fig.  166),  from  which  the 
spines  will  presently  project.  When  this  process  is  complete,  the 
whole  embryo,  with  the  exception  of  the  part  where  the  young 
Star-fish  is  placed,  grows  opaque  ;  it  fades,  as  it  were,  begins  to 
shrink  and  contract,  and  presently  drops  to  the  bottom,  where 

it  attaches  itself  by  means  of 
short  .arms  (//',  Fig.  166), 
covered  with  warts,  which  act 
w,  as  suckers,  and  are  placed  just 
above  the  mouth.  As  soon  as 
the  Star-fish  lias  thus  secured 
w,  itself,  it  begins  to  resorb  the 
whole  external  structure  de 
scribed  above ;  the  water-tubes, 
the  plastrons,  and  the  compli 
cated  system  of  arms  connected 
V  witli  them,  disappear  within  the 
little  Star-fish  ;  it  swallows  up, 
so  to  speak,  the  first  stage  of  its 
own  existence  ;  it  devours  its 
own  larva,  which  now  becomes 
part  and  parcel  of  the  new  ani 
mal.  Next  the  two  surfaces, 
the  back  and  lower  surface,  on 
which  the  arms  are  now  marked 
out,  while  the  tentacles,  suck 
ers,  and  spines  have  already 
assumed  a  certain  prominence, 
approach  each  other.  At  this 
time,  however,  the  arms  are 
not  in  one  plane  ;  both  the  back 
and  the  lower  surface  are 
curved  in  a  kind  of  spiral ;  they  begin  to  flatten  ;  the  arms  spread 
out  on  one  level,  —  and  now  the  two  surfaces  draw  together, 
meeting  at  the  circumference,  and  enclosing  between  them  the 
internal  organs,  which,  as  we  have  seen,  are  already  formed  and 
surrounded  by  walls  of  their  own,  before  the  two  walls  of  the  bod) 

Fig.  167.     Fig.  166  seen  in  profile,  lettering  as  l>efore. 


EMBRYOLOGY    OF   ECHINODERMS. 


129 


close  thus  over  them.  Fig.  168  represents  the  upper  surface  of 
the  Star-fish  just  before  this  junction  takes  place.  The  compli 
cated  structure  of  the  Brachiolaria,  as  the  larva  of  the  Star-fish 
has  been  called,  hitherto  so  essential  to  the  life  of  the  animal,  by 
which  it  has  been  supported,  moved  about  in  the  water,  and.  pro 
vided  with  food  during  its  immature  condition,  has  made  a  final 
contribution  to  its  further  development  by  the  process  of  resorp- 
tion  described  above,  and  has  wholly  disappeared  within  the  Star 
fish.  At  this  stage  the  rays  are  only  just  marked  out,  as  five 
lobes  around  the  margin  ;  Fig.  169  represents  the  lower  surface 
at  the  same  moment,  with  the  open  mouth  (w),  around  which 

Fig.  168.  Fig.  170. 


the  tentacles  (t)  are  just  beginning  to  appear  ;  while  Fig.  170 
shows  us  the  animal  at  a  more  advanced  stage,  after  the  two  sur 
faces  have  united.  It  has  now  somewhat  the  outline  of  a  Maltese 
cross,  the  five  arms  being  more  distinctly  marked  out,  while  the 
tentacles  have  already  attained  a  considerable  length  (Fig.  171), 
and  the  dorsal  plates  have  become  quite  distinct.  Fig.  172  rep 
resents  the  same  animal,  at  the  same  age,  in  profile.  This  period, 
in  which  we  have  compared  the  form  of  the  Star-fish  to  that  of  a 
Maltese  cross,  is  one  of  long  duration  ;  two  or  three  years  must 
elapse  before  the  arms  will  elongate  sufficiently  to  give  it  a  star- 
shaped  form,  and  before  the  pedicellariae  make  their  appearance, 

Fig.  163.    Star-fish  which  has  just  resorbed  the  larva,  seen  from  the  back  ;  b  madreporic  opening. 
Fig.  169.    Fig.  168,  seen  from  the  mouth  side  ;  m  mouth,  t  tentacles. 

Fig.  170.    Young  Star-fish  which  has  become  symmetrical,  seen  from  the  back  ;  t '  odd  tentacle. 
17 


130 


MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 


and  it  is  only  then  that  it  can  be  at  once  recognized  as  the  young 
of  our  common  Star-fish.     Even  then,  after  it  has  assumed  its  ulti 


mate  outline,  it  lacks  some  features  of  the  adult,  having  only  two 
rows  of  tentacles,  whereas  the  full-grown  Star-fish  has  four. 

Sea-ur chins. 

This  extraordinary  process  of  development  which  we  have  ana 
lyzed  thus  at  length  in  the  history  of  the  Star-fish,  but  which  is 

Fig.  174. 


Fig.  173. 


equally  true  of  all  Echinoderms,  has  been  hitherto  described  (so 
far  as  it  was  known)  under  the  name  of  the  plutean  stages  of 

Fig.  171.    Lower  side  of  ray  of  young  Star-fish  ;  m  mouth,  b  madreporic  body,  «  eye-speck. 

Fig.  172.    Young  Star-fish  seen  in  profile  ;  t'  odd  tentacle  at  extremity  of  arm. 

Figs.  173, 174, 175.  Young  larvse  of  Toxopneustes  in  different  stages  of  development ;  e' -  eIT  arms, 
v-v"  vibratile  chord,  w  w'  earlets  (water-tubes),  a  od  c  digestive  system,  r'-r'"  solid  rods  of  arms, 
m  mouth,  b  madreporic  opening. 


EMBRYOLOGY    OF    ECHINODERMS. 


131 


growth.  In  these  early  stages  the  young,  or  the  so-called  larvae 
of  Echinoderms,  have  received  the  name  of  Pluteus  on  account 
of  their  ever-changing  forms.  Let  us  look  for  a  moment  at  the 
plutean  stages  of  the  Sea-urchin,  as  they  differ  in  some  points 
from  those  of  the  Star-fish.  In  the  Pluteus  of  our  common 
Sea-urchins  (see  Fig.  176),  the  arms  are  supported  by  a  frame 
work  of  solid  limestone  rods,  which  do  not  exist  in  that  of 
the  Star-fish,  and  which  give  to  the  larva  of  the  Sea-urchin  a  re 
markable  rigidity.  They  are  formed  very  early,  as  may  be  seen 


Fig.  175. 


in  Fig.  173,  representing  the  little  Sea-urchin  before  any  arms 
are  discernible,  though  the  limestone  rods  are  quite  distinct. 
Figs,  173,  174,  175,  may  be  compared  with  Figs.  160,  162,  165, 
of  the  young  Star-fish,  where  it  will  be  seen  that  the  general  out 
line  is  very  similar,  though,  on  account  of  the  limestone  rods,  the 
Pluteus  of  the  Sea-urchin  seems  somewhat  more  complicated.  In 


132 


MARINE   ANIMALS    OF    MASSACHUSETTS    BAY. 


Fig.  176  the  young  Sea-urchin  has  so  far  encroached  upon  the 
Pluteus  that  it  forms  the  essential  part  of  the  body,  the  arms  and 

Fig.  176. 


rods  appearing  as  mere  appendages.  Fig.  177  shows  the  same 
animal  when  we  looked  down  upon  it  in  its  natural  attitude  ;  the 
Sea-urchin  is  carried  downward,  and  the  arms  stretch  in  every  di 
rection  around  it.  In  Fig.  178  the  Pluteus  is  already  in  process 
of  absorption  ;  in  Fig.  179  it  has  wholly  disappeared  ;  in  Figs. 

Fig.  176.     Adult  larva  of  Toxopneustes,  /  brachilar  appendages. 


EMBRYOLOGY    OF    ECHIXODERMS. 


133 


180  and  181  we  have  different  stages  of  the  little  Sea-urchin,  with 
its  spines  and  suckers  of  a  large  size  and  in  full  activity.     The 


Tig.  17' 


Fig.  178. 


Fig.  179. 


appearance  of  the  Sea-urchin,  as  soon  as  this  larva  or  Pluteus  is 
completely  absorbed,  is  much  more  like  that  of  the  adult  than  is 
the  Star-fish  at  the  same  stages,  in  which,  as  we  have  seen,  there 
is  a  transition  period  of  considerable  duration. 

Fig.  177.    Fig.  176  seen  endways. 

Fig.  178.    The  Sea-urchin  resorbing  the  arms  of  the  larva. 

Fig.  179.    Half  a  young  Sea-urchin  immediately  after  resorption  of  the  larva  ;  s"  s"  spines,  t'  t'  am- 
bulacral  tentacles. 


134 


MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 


Fig.  ISO. 


Fig.  180.     Young  Sea-urchin  older  than  Fig.  179  ;  1 1'  tentacles,  s"  s'"  spines. 

Fig.  181.     Still  older  Sea-urchin  5  1 1  tentacles,  a  anus,  p  pedicellaritu  5  shell  one  sixteenth  of  an  inch 
in  diameter. 


EMBRYOLOGY    OF    ECHINODERMS.  135 

Opliiurans. 

Fig.  183  represents  an  Ophiuran  undergoing  the  same  process 
of  growth,  at  a  period  when  the  larva  is  most  fully  developed,  and 
before  it  begins  to  fail.  By  the  limestone  rods  which  support  the 
arms,  the  Pluteus  of  the  Ophiuran,  here  represented,  resembles 
that  of  the  Sea-urchin  more  than  that  of  the  Star-fish,  while  by 
the  character  of  the  water-tubes  and  by  its  internal  organization 
it  is  more  closely  allied  to  the  latter.  It  differs  from  both,  how 
ever,  in  the  immense  length  of  two  of  the  arms  ;  these  arms 
being  the  last  signs  of  its  plutean  condition  to  disappear ;  when 
the  young  Ophiuran  has  absorbed  almost  the  whole  Pluteus,  it 
still  goes  wandering  about  with  these  two  immense  appendages, 
which  finally  share  the  fate  of  all  the  rest.  Fig.  182  represents 


Fig.  182. 


an  Ophiuran  at  the  moment  when  the  process  of  resorption  is 
nearly  completed,  though  the  arms  of  the  Pluteus,  greatly  di 
minished,  are  still  to  be  seen  protruding  from  the  surface  of  the 
animal. 

This  mode  of  development,  though   common  to  all  Echino- 

Fig.  182.    Ophiuran  which  has  resorbed  the  whole  larva  except  the  two  long  arms,  y  y'  limestone 
rods  of  young  Ophiuran,  r  middle  of  back  ;  lettering  as  ia  Fig.  183. 


136  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

Fig.  183. 


Fig.  183.     Larva  of  Ophiuran  •,  c'  -  eiv  arms,  r'  riv  solid  rods,  v  v'  vibratile  chord,  w  w'  water  system, 
b  madreporic  bady,  ad  digestive  system. 


EMBRYOLOGY    OF   ECHINODERMS.  137 

derms,  appears  under  very  different  conditions  in  some  of  them. 
There  are  certain  Star-fishes,  Ophiurans,  and  Holothurians,  pass 
ing  through  their  development  under  what  is  known  as  the 
sedentary  process.  The  eggs  are  not  laid,  as  in  the  cases  de 
scribed  above,  but  are  carried  in  a  sort  of  pouch  over  the  mouth 
of  the  parent  animal,  where  'they  remain  till  they  attain  a  stage 
corresponding  to  that  of  Fig.  168  of  the  Star-fish,  and  having 
much  the  same  cross-shaped  outline,  when  they  escape  from  the 
pouch  (as  the  young  Ophiopholis,  Fig.  184),  and  swim  about  for 
the  first  time  as  free  animals.  Fig.  185  represents  a  cluster  of 

Tig.  184.  Fig.  185. 


young  Star-fishes  of  the  sedentary  kind  at  about  this  period.  But 
while  this  mode  of  growth  seems  at  first  sight  so  different,  we  shall 
find,  if  we  look  a  little  closer,  that  it  is  essentially  the  same,  and 
that,  though  the  circumstances  under  which  the  development  takes 
place  are  changed,  the  process  does  not  differ.  The  little  Star 
fish  or  Ophiuran,  in  the  pouch,  becomes  surrounded  by  the  same 
plutean  structure  as  those  which  are  laid  in  the  egg  ;  it  is  only 
more  contracted  to  suit  the  narrower  space  in  which  they  have  to 
move  ;  and  the  water-tubes  on  which  the  upper  and  lower  sur 
faces  of  the  body  arise,  the  shields,  spreading  out  into  arms  at  the 
corners,  exist,  fully  developed  or  rudimentary,  in  the  one  as  much 
as  in  the  other,  and  when  no  longer  necessary  to  its  external  ex 
istence  they  are  resorbed  in  the  same  way  in  both  cases.  This 
singular  process  of  development  has  no  parallel  in  the  animal 

Fig.  184.    Young  Ophiuran  which  has  resorbed  the  whole  larva  ;  r  middle  plate  of  back. 
Fig.  185.     Cluster  of  eggs  of  Star-fishes  placed  over  the  mouth  of  the  parent. 
18 


138  MARINE   ANIMALS    OF   MASSACHUSETTS    BAY. 

kingdom,  although  the  growth  of  the  young  Echinoderm  on 
the  Brachiolaria  may  at  first  sight  remind  us  of  the  budding  of 
the  little  Medusa  on  the  Hydroid  stock,  or  even  of  the  passage  of 
the  insect  larva  into  the  chrysalis.  But  in  both  these  instances, 
the  different  phases  of  the  development  arc  entirely  distinct ;  the 
Hydroid  stock  is  permanent,  continuing  to  live  and  grow  and  per 
form  its  share  in  the  cycle  of  existence  to  which  it  belongs,  after 
the  Medusa  has  parted  from  it  to  lead  a  separate  life,  or  if  the 
latter  remains  attached  to  the  parent  stock  after  it  has  entered 
upon  its  own  proper  functions.  The  life  of  the  caterpillar, 
chrysalis  and  butterfly,  is  also  distinct  and  definitely  marked ;  the 
moment  when  the  animal  passes  from  one  into  the  other  cannot 
be  mistaken,  although  the  different  phases  are  carried  on  suc 
cessively  and  not  simultaneously,  as  in  the  case  of  the  Acalephs. 
But  in  the  Echinoderms,  on  the  contrary,  though  the  aspect  of  the 
Brachiolaria,  or  plutean  stage,  is  so  different  from  that  of  the  adult 
form,  that  no  one  would  suppose  them  to  belong  to  the  same  ani 
mal,  yet  these  two  stages  of  growth  pass  so  gradually  into  one 
another,  that  one  cannot  say  when  the  life  of  the  larva  ceases,  and 
that  of  the  Echinoderm  begins. 

The  bearing  of  embryology  upon  classification  is  becoming 
every  day  more  important,  rendering  the  processes  of  develop 
ment  among  animals  one  of  the  most  interesting  and  instruc 
tive  studies  to  which  the  naturalist  can  devote  himself,  in  the 
present  state  of  his  science.  The  accuracy  of  this  test,  not  only 
as  explaining  the  relations  between  animals  now  living,  but  as 
giving  the  clew  to  their  connection  with  those  of  past  times,  can 
not  but  astonish  any  one  who  makes  it  the  basis  of  his  investiga 
tions.  The  comparison  of  embryo  forms  with  fossil  types  is  of 
course  difficult,  and  must  in  many  instances  be  incomplete,  for 
while,  in  the  one  case,  death  and  decay  have  often  half  destroyed 
the  specimen,  in  the  other,  life  has  scarcely  stamped  itself  in 
legible  characters  on  the  new  being.  Yet,  whenever  such  com 
parisons  have  been  successfully  carried  out,  the  result  is  always 
the  same  ;  the  present  representatives  of  the  fossil  types  recall  in 
their  embryonic  condition  the  ancient  forms,  and  often  explain 
their  true  position  in  the  animal  kingdom.  One  of  the  most  re 
markable  examples  of  this  in  the  type  we  are  now  considering, 


EMBRYOLOGY    OF    ECHINODERMS.  139 

is  that  of  the  Comatula  already  mentioned.  Its  condition  in 
the  earlier  stages  of  growth,  when  it  is  provided  with  a  stem,  at 
once  shows  its  relation  to  the  old  stemmed  Crinoids,  the  earliest 
representatives  of  the  class  of  Echinoderms. 

These  coincidences  are  still  more  striking  among  living  ani 
mals,  where  they  can  be  more  readily  and  fully  traced,  and  often 
give  us  a  key  to  their  relative  standing,  which  our  knowledge  of 
their  anatomical  structure  fails  to  furnish.  This  is  perhaps  no 
where  more  distinctly  seen  than  in  the  typo  of  Radiates,  where 
the  Acalephs  in  their  first  stages  of  growth,  that  is,  in  their  Hy- 
droid  condition,  remind  us  of  the  adult  forms  among  Polyps, 
showing  the  structural  rank  of  the  Acalephs  to  be  the  highest, 
since  they  pass  beyond  a  stage  which  is  permanent  with  the 
Polyps  ;  while  the  adult  forms  of  the  Acalephs  have  in  their  turn 
a  certain  resemblance  to  the  embryonic  phases  of  the  class  next 
above  them,  the  Echinoderms.  Within  the  limits  of  the  classes, 
the  same  correspondence  exists  as  between  the  different  orders ; 
the  embryonic  forms  of  the  higher  Polyps  recall  the  adult  forms 
of  the  lower  ones,  and  the  same  is  true  of  the  Acalephs  as  far 
as  these  phenomena  have  been  followed  and  compared  among 
them.  In  the  class  of  Echinoderms  the  comparison  has  been 
carried  out  to  a  considerable  extent,  their  classification  has 
hitherto  been  based  chiefly  upon  the  ambulacral  system,  so 
characteristic  of  the  class,  but  so  unequally  developed  in  the 
different  orders.  This  places  the  Holothurians,  in  which  the 
ambulacral  system  has  its  greatest  development,  at  the  head  of 
the  class  ;  next  to  them  come  the  Sea-urchins  or  Echinoids  ; 
then  the  Star-fishes ;  then  the  Ophiurans  and  Crinoids,  in  which 
the  ambulacral  system  is  reduced  to  a  minimum.  Another 
basis  for  classification  in  this  type,  which  gives  the  same  re 
sult,  is  the  indication  of  a  bilateral  symmetry  in  some  of  the 
orders.  In  the  Holothurians,  for  instance,  there  is  a  decided 
tendency  toward  the  establishment  of  a  posterior  and  anterior 
extremity,  of  a  right  and  left,  an  upper  and  lower  side  of  the 
body.  In  the  Sea-urchins,  in  many  of  which  the  mouth  is  out 
of  centre,  placed  nearer  one  side  than  the  other,  this  tendency 
is  still  apparent,  while  in  the  three  lower  groups,  the  Star-fishes, 
Ophiurans,  and  Crinoids,  it  is  almost  entirely  lost,  in  the  equal 


140  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

division  of  identical  parts  radiating  from  a  common  centre.  A 
comparison  of  the  embryonic  and  adult  forms  in  these  orders, 
confirms  entirely  this  classification  based  npon  structural  features. 
The  Star-fishes,  in  their  earlier  stages,  resemble  the  mature  Ophi- 
urans,  while  the  Crinoids,  the  lowest  group  of  all,  retain  through 
out  their  whole  existence  many  features  characteristic  of  the 
embryonic  conditions  of  the  higher  Echiiioderms.  In  this  prin 
ciple  of  classification,  already  so  fertile  in  results,  we  may  hope  to 
find,  in  some  instances,  the  solution  of  many  perplexing  points 
respecting  the  structural  rank  of  animals,  the  confirmation  of 
classifications  already  established ;  in  others,  an  insight  into  the 
true  relations  of  groups  which  have  hitherto  been  divided  upon 
purely  arbitrary  grounds. 


DISTRIBUTION    OF   LIFE   IN    THE    OCEAN.  141 


DISTKIBUTION     OF     LIFE    IN    THE 
OCEAN. 

WE  have  seen  that  while  our  bay  is  rich  in  certain  species,  it  is 
wholly  deficient  or  but  scantily  supplied  with  others,  and  that 
the  character  of  the  animals  inhabiting  its  waters  is  more  or  less 
directly  connected  with  general  physical  conditions.  Such  an 
area,  limited  though  it  be,  gives  us  some  insight  into  the  laws 
which,  in  their  wider  application,  control  the  distribution  of  ma 
rine  life  along  the  shores  of  the  most  extensive  continents.  The 
coast  of  Massachusetts,  taken  as  a  whole,  is  like  that  of  New 
England  generally,  a  rocky  coast ;  yet  it  has  its  sandy  and  muddy 
beaches,  and  though  it  lies  for  a  great  part  open  to  the  sea,  it  has 
nevertheless  its  sheltered  harbors,  its  quiet  bays  and  snug  re 
cesses. 

A  comparison  of  these  limited  localities  with  far  more  exten 
sive  reaches  of  shore,  where  similar  physical  conditions  prevail, 
shows  that  they  reproduce,  in  fainter  and  less  various  characters 
of  course,  in  proportion  to  their  narrower  boundaries,  but  still 
with  a  certain  fidelity,  the  same  combinations  of  animal  and 
vegetable  life.  In  other  words,  a  sandy  beach,  however  small, 
gives  us  some  idea  of  the  nature  of  the  animals  we  may  look  for 
on  any  sandy  coast,  as,  for  instance,  clams  of  various  kinds, 
razor-shells,  quahogs,  snails,  &c.,  creatures  who  can  penetrate 
the  sand,  drag  themselves  through  it  or  over  it,  leaving  their 
winding  trails  as  they  go,  and  to  whom  the  conditions  prevailing 
in  such  spots  are  genial.  So  the  narrowest  mud  flat  on  the  sea 
shore  or  muddy  beach  will  give  us  the  same  dead  and  inanimate 
aspect  which  characterizes  a  more  extensive  coast  of  like  charac 
ter,  where  the  gases  always  generated  in  mud  are  deadly  to 
many  kinds  of  animals,  and  the  beings  who  find  a  home  there 
are  of  closely  allied  species,  chiefly  a  variety  of  worms,  who  bur 
row  their  way  into  the  mud,  and  seem  to  court  the  miasma  so 


142  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

fatal  to  other  creatures.  The  same  is  true  of  any  stony  beach  or 
rocky  shore  not  more  than  a  quarter  of  a  mile  in  length  ;  it  gives 
us  an  idea  of  the  animal  population  on  any  similar  coast  of  great 
er  extent. 

These  correspondences  are  of  course  modified  by  differences 
in  climatic  conditions.  The  animals  on  a  sandy  beach  or  a  rocky 
shore,  on  the  coast  of  Great  Britain,  for  instance,  are  not  absolute 
ly  identical  with  those  of  a  sandy  beach  or  a  rocky  shore  on  the 
coast  of  New  England,  but  they  are  more  or  less  nearly  related 
to  them.  Naturalists  refer  to  this  reiteration,  all  the  world  over, 
of  like  organic  combinations  under  similar  circumstances,  when 
they  speak  of  "  representative  species."  The  aggregate  result  is 
the  same,  though  the  individual  forms  are  slightly  modified. 
And  here  lies  one  secret  of  the  infinite  variety  in  nature,  by 
which  the  old  seems  ever  new,  and  the  same  thought  has  an  eter 
nal  freshness  and  originality,  endlessly  repeated,  yet  never  hack 
neyed. 

In  this  sense  our  bay  presents,  on  a  miniature  scale,  a  variety 
of  physical  and  organic  combinations,  which  may  be  compared  to 
those  more  extensive  divisions  in  the  geographical  distribution  of 
animals  and  plants,  called  by  naturalists  zoological  or  botanical 
provinces  or  districts,  the  animal  and  vegetable  populations  of 
which  are  technically  designated  as  their  faunae  and  florae.  Such 
organic  realms,  as  we  may  call  them,  have  long  been  recognized 
on  land,  and  the  most  extensive  among  them  are  easily  distin 
guished.  No  one  will  fail  to  recognize  the  tropical  zone,  with  its 
royal  dynasty  of  palms  and  all  the  accompanying  glories  of  a  trop 
ical  vegetation,  its  birds  of  brilliant  plumage,  its  large  Mammalia, 
lions,  tigers,  panthers,  elephants,  and  its  great  rivers  haunted  by 
gigantic  reptiles.  Nor  is  the  representation  of  vegetable  and  ani 
mal  life  less  characteristic  in  the  temperate  zone,  where  the  oak 
is  monarch  of  the  woods,  with  all  his  attendant  court  of  elms, 
walnuts,  beeches,  birches,  maples,  and  the  like,  where  birds  of 
more  sober  hues,  but  sweeter  voices,  take  the  place  of  the  bril 
liant  parrots  and  many-tinted  humming-birds  of  the  tropical 
forest ;  while  buffaloes,  bears,  wolves,  foxes,  and  deer  represent 
the  larger  Mammalia.  In  the  arctic  zone,  though  marked  by 
peculiar  and  distinctive  features,  vegetation  has  dwindled  to  a 


DISTRIBUTION    OF    LIFE    IN   THE    OCEAN.  143 

minimum ;  the  birds  are  chiefly  gulls  and  ducks,  which  go 
there  for  the  breeding  season  in  the  summer,  and  the  reindeer 
and  polar  bears  are  almost  sole  possessors  of  the  snow  and  ice 
fields  ;  but  this  meagreness  in  the  representation  of  the  larger 
land  Mammalia  is  amply  compensated  in  the  numbers  of  heavy 
aquatic  Mammalia,  the  whales,  walruses,  seals,  and  porpoises  of 
the  Arctic  seas. 

During  the  last  half-century,  since  the  geographical  distribu 
tion  of  animals  and  plants  has  become  a  subject  of  more  careful 
investigation  among  naturalists,  these  broad  zones  of  the  earth's 
surface,  with  their  characteristic  populations  and  vegetation,  have 
been  subdivided,  according  to  more  limited  and  special  combina 
tions  of  organic  forms,  into  narrower  zoological  and  botanical 
areas.  The  application  of  these  results  to  marine  life  is  however 
of  much  more  recent  date,  and  indeed  it  would  seem  at  first 
sight,  as  if  the  water,  from  its  own  nature,  could  hardly  impose  a 
barrier  so  impassable  as  the  land.  The  localization  of  the  marine 
faunaB  and  florae  is  nevertheless  as  distinct  as  that  of  terrestrial 
animals  and  plants,  and  late  investigations  have  done  much 
to  explain  the  connection  of  this  distribution  with  physical  con 
ditions. 

A  glance  at  the  coast  of  our  own  continent,  starting  from  the 
high  north  and  making  the  circuit  of  its  shores,  from  Baffin's 
Bay  to  Behring's  Straits,  will  show  us  to  what  a  variety  of  physi 
cal  influences  the  animals  who  live  along  its  shores  are  subjected. 
On  the  shores  of  Baffin's  Bay,  especially  on  the  inner  coast  of 
Greenland,  where  the  glaciers  push  their  way  down  to  the  very 
brink  of  the  water,  and  annually  launch  their  southward-bound 
icebergs,  we  shall  hardly  expect  to  find  a  very  abundant  littoral 
fauna.  On  its  western  shore,  where  the  ice  does  not  advance  so 
far,  and  a  greater  surface  of  rock  is  exposed,  the  circumstances 
are  more  favorable  to  the  development  of  animal  life.  Here 
abound  the  winged  Mollusks  (Pteropods),  often  swept  down  to 
the  coast  of  Nova  Scotia  by  the  cold  current  from  Baffin's  Bay  ; 
the  "  whale  feed,"  as  the  fishermen  call  them,  because  the  whales 
devour  them  voraciously.  Here  occur  also  many  compound 
Mollusks,  especially  a  variety  of  Ascidians,  and  the  highly  colored 
stocks  of  Bryozoa.  With  them  is  found  the  Comatula  of  the 


144  MARINE   ANIMALS    OF    MASSACHUSETTS    BAY. 

northern  waters,  one'  of  the  few  modern  Crinoids,  and  beside 
these  a  number  of  Star-fishes,  Sea-urchins,  and  Holothurians,  not 
differing  so  essentially  from  those  already  described  as  to  require 
special  mention. 

Along  the  shore  of  Labrador  and  Newfoundland,  the  coast  is 
wholly  rocky,  and  especially  about  Newfoundland  it  is  deeply  in 
dented  with  bays.  Here  there  is  ample  opportunity  for  the 
growth  of  certain  kinds  of  animals  in  sheltered  nooks.  The 
number  of  species  is,  however,  much  greater  along  the  shores  of 
Maine,  Nova  Scotia,  and  New  Brunswick  than  in  Labrador, 
owing  no  doubt  to  the  milder  climate.  The  beautiful  shore  of 
Maine,  with  its  countless  islands,  and  broken,  picturesque  outline, 
is  very  rich  in  species.  Parts  of  this  coast  are  remarkable  for  a 
variety  of  naked  Mollusks,  as  well  as  the  great  numbers  of 
bright-colored  Actiniae,  and  also  for  the  more  brilliant  kinds  of 
Holothurians,  the  Cuvieria,  and  the  like.  The  latter  are  especially 
abundant  in  the  Bay  of  Fundy,  and  here  also  occurs  the  only 
Northern  representative  on  our  coast  of  the  Sea-fans  or  Gorgonias, 
so  common  on  the  shores  of  Florida. 

Farther  south,  from  Cape  Cod  to  Cape  Hatteras,  the  character 
of  the  coast  changes  ;  it  becomes  more  sandy,  and  though  here 
and  there  the  aspect  is  varied  by  a  rocky  promontory  or  a  stony 
beach,  yet  the  general  character  is  flat  and  sandy.  With  this 
new  character  of  the  shore,  the  fauna  is  also  greatly  modified,  and 
it  is  worthy  of  remark,  that  while  thus  far  the  representative 
species  have  reflected  the  character  of  animals  to  the  north  of 
them,  they  now  begin  to  represent  rather  those  of  the  Carolina 
shores.  South  of  Cape  Cod  come  in  a  kind  of  Scallop  and  Peri 
winkle,  very  different  from  the  larger  Scallops  found  on  the  coast 
of  Maine  and  the  British  Provinces  ;  our  Sea-urchin  is  replaced 
by  the  Echinocidaris,  with  its  few  long  spines,  and  an  entirely  new 
set  of  Crustacea  and  Worms  make  their  appearance  on  this  more 
sandy  bottom.  And  here  we  must  not  forget  that  not  only  is  the 
aspect  of  the  animal  life  changed,  as  we  pass  from  a  rock-bound 
to  a  sandy  coast,  but  that  of  the  vegetation  also.  The  various 
many-tinted  sea-weeds  of  the  rocky  shore  disappear  almost  en 
tirely,  and  their  place  is  but  poorly  supplied  by  the  long  eel- 
grass,  which  is  almost  the  only  marine  plant  to  be  found  in  such 


DISTRIBUTION    OF    LIFE    IN    THE    OCEAN.  145 

a  locality.  Beside  its  more  sandy  character,  the  coast  from  Capo 
Cod  to  Cape  Hatteras  is  affected  by  the  large  amount  of  fresh 
water  poured  into  the  sea  along  its  whole  line,  greatly  modifying 
the  character  of  the  shore  animals.  The  Hudson,  the  Delaware, 
the  Susquehanna,  the  Potomac,  the  James,  the  Roanoke,  and  the 
large  estuaries  connected  with  some  of  these  rivers,  give  a  very 
peculiar  character  to  the  shore,  and  bring  down,  not  only  a  vast 
supply  of  fresh  water,  but  also  a  large  quantity  of  detritus  of  all 
sorts  from  the  land.  Under  these  circumstances  life  would  be 
impossible  for  many  of  the  animals  which  live  farther  north. 
The  only  locality  on  the  North  Atlantic  shore,  where  the  condi 
tions  are  somewhat  similar,  is  at  the  mouth  of  the  St.  Lawrence, 
that  great  drainage-bed  through  which  the  Canadian  lakes  empty 
their  superfluous  waters  into  the  Gulf  of  St.  Lawrence. 

The  whole  coast  of  the  Carolinas,  from  Cape  Hatteras  to 
Florida,  is  a  sandy  beach  ;  but  though  in  this  respect  it  resembles 
that  immediately  to  the  north  of  it,  it  differs  greatly  in  other 
features.  Comparatively  little  fresh  water  is  poured  into  the 
ocean  along  this  shore,  and  its  more  southerly  range,  instead 
of  being  protected  by  sand-spits  like  Pamlico  and  Albemarle 
Sounds,  or  broken  by  estuaries  and  inlets  like  the  coast  of  Vir 
ginia,  lies  broadly  open  to  the  sea.  On  its  extensive  beaches 
we  have  the  large  Pholas,  burrowing  deep  below  the  surface, 
and  the  Cerianthus,  those  long,  cylindrical  Actiniae,  enclosed  in 
sheaths,  with  their  bright  crowns  of  gayly-colored  tentacles  ;  the 
free  colonies  of  Halcyonoids  abound  also  on  this  coast,  and  a  new 
set  of  Sea-urchins  (Spatangoids  and  Clypeastroids)  make  their 
appearance. 

Farther  south,  along  the  Florida  coast,  a  new  element  comes 
in,  that  of  the  coral  reefs,  enclosing  shallow  channels  near  the 
shore,  and  thus  providing  sheltered  harbors  on  their  leeward  side, 
while  on  their  seaward  side  they  slope  steeply  to  the  ocean.  Be 
side  this,  the  reef  itself  affords  a  home  for  a  great  variety  of 
creatures,  who  bore  their  way  into  it  and  live  in  its  recesses,  as 
some  insects  live  in  the  bark  of  trees.  Perhaps  a  more  favor 
able  combination  of  circumstances  for  the  development  of  marine 
life  does  not  exist  anywhere  than  about  the  coral  reefs  of 
Florida,  and  certainly  nowhere  is  there  a  more  rich  and  varied 

19 


146  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

littoral  fauna,  especially  on  their  western  shore  within  the  Gulf 
of  Mexico.  Here  swims  the  Portuguese  Man-of-War,  borne  gayly 
along  on  the  surface  of  the  water  by  its  brilliant  float,  here  the 
blue  Velella  sets  its  oblique  sail  to  the  wind,  and  hosts  of  the 
lighter  and  more  brightly  tinted  corals  fringe  the  shore  with  a 
many-colored  shrubbery.  In  these  waters  are  also  found  the  blue 
and  yellow  Angel-fish,  the  Parrot-fish  (Scams),  and  the  strange 
Porcupine-fish  (Diodon).  Vegetable  life  is  comparatively  scanty 
in  these  tropical  waters,  where  there  are  scarcely  any  sea-weeds, 
except  the  corallines  or  limestone  Alga3  of  the  reefs.  The  shore 
of  the  Gulf  of  Mexico,  as  a  whole,  has  much  the  same  character 
as  that  of  the  Carolinas,  until  we  reach  the  point  where  the 
mountains  and  plateau  of  Mexico  come  down  to  the  coast.  From 
this  point  to  the  Isthmus  of  Panama  the  coast  is  again  rocky. 

Crossing  the  Isthmus  and  following  the  Pacific  shore  of  the 
continent  northward,  we  find  a  sandy  open  shore  alternating  with 
rocky  beaches  as  far  north  as  Acapulco.  Along  this  coast  there 
is  to  be  found  a  great  variety  of  corals,  especially  Sea-fans, 
growing  on  the  rocks,  but  no  reef.  The  Pocillopora,  an  Acale- 
phian  coral,  the  Pacific  representative  of  the  Millepore  of  Florida, 
is  especially  abundant.  On  the  peninsula  of  Lower  California  we 
come  again  upon  a  rocky  coast,  with  steep  bluffs,  extending  into 
the  sea.  Within  the  Gulf  of  California  are  found,  on  its  sandy 
coast,  peculiar  kinds  of  Sea-urchins,  Spatangoids,  and  Clypeas- 
troids,  which  occur  nowhere  else  on  this  coast.  From  Cape  St. 
Lucas  up  to  the  Straits  of  Fuca,  with  the  exception  of  the  large 
fresh-water  estuary  which  forms  the  port  of  San  Francisco,  there 
is  not  a  harbor  of  any  consequence.  The  whole  shore  is  most 
inhospitable,  and  the  violent  northwest  winds  in  summer,  and 
the  southeast  winds  in  winter,  render  it  still  more  bleak  and  diffi 
cult  of  approach.  In  consequence  of  these  conditions,  the  fauna 
is  scanty  along  a  great  part  of  the  shore ;  the  best  spots  for  collect 
ing  are  the  beaches,  near  the  head  of  the  peninsula,  opposite  the 
islands  of  Santa  Barbara  and  San  Diego,  and  that  within  the 
harbor  of  San  Francisco.  On  the  former,  large  Craw-fishes  abound 
(Palinurus),  akin  to  those  of  Florida,  though  specifically  different 
from  them.  In  the  latter,  the  great  amount  of  fresh  water 
prevents  the  fauna  from  being  exclusively  marine  ;  this  harbor  is, 


DISTRIBUTION    OF   LIFE    IN    THE    OCEAN.  147 

nevertheless,  the  great  centre  of  the  viviparous  fishes,  and  con 
tains  also  a  large  variety  of  peculiarly  shaped  Sculpins. 

Farther  north,  between  the  Straits  of  Fuca  and  the  island  of 
Sitka,  the  shore  resembles  that  of  Maine,  with  its  many  islands, 
bays,  and  inlets  ;  a  succession  of  long,  narrow  islands  forms  a 
barrier  along  the  coast,  enclosing  the  shore  waters,  so  as  almost 
to  make  them  into  an  inland  sea.  But  little  fresh  water  empties 
upon  this  part  of  the  coast,  and  here,  where  the  salt  water  is  little 
modified  by  any  deposit  from  the  land,  but  where  the  violence  of 
the  ocean  is  broken  by  this  barrier  of  islands,  there  is  a  full  devel 
opment  of  marine  life.  The  shores  of  the  Gulf  of  Georgia,  and 
those  of  Vancouver's  Island,  seem  to  be  especially  the  home  of 
the  Star-fishes.  The  fauna  of  this  locality  has  been  but  little  in 
vestigated,  and  yet  the  number  of  species  of  Star-fishes  known 
from  there  is  greater  than  from  any  other  region  ;  many  of  them 
are  of  colossal  size,  measuring  some  four  feet  in  diameter.  This 
coast  seems  also  very  favorable  for  the  development  of  Hydroids, 
in  consequence  of  which  its  waters  swarm  with  a  variety  of  Jelly- 
fishes.  The  Pennatula,  that  pretty  compound  Halcyonoid,  with 
its  feather-like  sprays,  is  another  characteristic  type  of  this  fauna. 
Beyond  this,  from  Sitka  to  Behring's  Straits,  the  same  rocky 
coast  prevails  as  in  Labrador  and  Greenland.  In  Behring's 
Straits  we  return  again  to  the  forests  of  beautiful  compound 
Mollusks,  or  rather  to  a  variety  of  "representative  species," 
resembling  the  Bryozoa  and  Ascidians  so  abundant  in  Baffin's 
Bay.  The  depth  of  the  water,  however,  is  much  less  here  than 
on  the  corresponding  Atlantic  coast,  where,  south  of  Greenland, 
along  the  shore  of  Labrador,  the  water  is  very  deep,  while  in 
Behring's  Straits  the  depth  is  not  greater  than  from  one  hundred 
to  one  hundred  and  twenty  fathoms.  The  respective  faunae  of 
these  two  shores  is  also  affected  by  the  difference  of  temperature, 
the  cold  current  from  Baffin's  Bay  sweeping  down  upon  the  coast 
of  Labrador,  while,  through  Behring's  Straits,  the  warm  current 
from  the  Pacific  pours  into  the  Arctic  Ocean. 

Thus  the  whole  coast  of  our  continent  is  peopled  more  or  less 
thickly  with  animals.  But  now  arises  a  new  set  of  inquiries  ; 
how  far  into  the  sea  do  these  animals  extend  ?  how  wide  is  their 
domain  ?  Do  they  wander  at  will  in  the  ocean,  or  are  they 


148  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

bound  by  any  law  to  keep  within  a  certain  distance  of  the  shore  ? 
These  questions  would  seem  to  be  easily  answered,  for  wherever 
we  go  on  the  surface  of  the  sea,  and  as  far  as  the  eye  can  pene 
trate  into  its  depths,  we  find  it  full  of  life  ;  and  yet  a  closer  ex 
amination  shows  that  all  these  beings  have  their  appointed  boun 
daries.  Along  the  shores,  animal  and  vegetable  life  seems  to  be 
distributed  in  certain  definite  combinations.  Those  who  are 
familiar  with  rocky  beaches  readily  recognize  the  different  bands 
of  color  produced  by  the  various  kinds  of  sea-weed  growing  at 
given  distances  between  high  and  low-water-mark.  First  comes 
the  olive  green  rockweed  (the  Fucus),  and  with  it  are  found  bar 
nacles  and  small  Crustacea,  myriads  of  which  are  to  be  seen  hop 
ping  about  in  this  rockweed  when  the  tide  is  out.  Below  these 
are  the  brown  crispy  Rhodersperms  and  Melanosperms,  and  asso 
ciated  with  them  are  Star-fishes,  Crabs,  and  Cockles.  Next  in 
order  is  the  Laminarian  zone.  Here  we  have  the  broad  fronds 
of  the  Laminaria,  the  "  devil's  aprons,"  as  the  fishermen  call 
them  ;  in  this  zone  is  the  home  of  the  Sea-urchin,  and  here  will 
be  found  also  a  few  small  fishes.  Lastly  we  have  the  Coralline 
zone,  so  called  on  account  of  the  lime  deposit  in  the  sea-weeds, 
giving  them  the  rigidity  of  corals  ;  among  these  the  Lobsters 
make  their  appearance,  and  here  are  to  be  found  also  numerous 
clusters  of  Hydroids,  the  nurses  of  the  Jelly-fishes. 

This  distribution  is  not  casual ;  these  belts  of  animal  and  vege 
table  life  are  sharply  defined  and  so  constantly  associated,  that 
they  must  be  controlled  by  the  same  physical  laws.  The  first 
important  investigations  on  this  subject  were  made  by  Orsted, 
the  distinguished  Danish  naturalist.  He  undertook  a  complete 
topographical  survey  of  the  coast  near  which  he  lived,  carrying 
his  soundings  to  a  depth  of  some  twelve  fathoms,  and  found  that 
both  the  fauna  and  flora  of  the  shore  were  divided,  according  to 
the  depth  of  the  water,  into  bands  of  vegetable  and  animal  life, 
corresponding  very  nearly  with  those  given  above.  His  observa 
tions  were,  however,  limited,  not  extending  beyond  the  neighbor 
hood  of  his  home.  It  is  to  Edward  Forbes,  the  great  English 
naturalist,  whose  short  life  was  so  rich  in  results  for  science,  that 
we  owe  a  more  complete  and  extensive  investigation  of  the  whole 
subject. 


DISTRIBUTION    OF   LIFE    IN    THE    OCEAN. 


149 


Diagram  of  a  rocky  beach. 


150  MARINE    ANIMALS    OF    MASSACHUSETTS    BAY. 

Aided  by  a  friend,  Captain  McAndrew,  who  placed  his  yacht 
at  his  disposal,  he  made  a  series  of  observations  on  the  British, 
Scandinavian,  and  Danish  coasts,  and  explored  also  with  the 
same  object  the  shores  of  the  Mediterranean.  Not  content  with 
sounding  the  present  ocean,  he  sunk  his  daring  plummet  in  the 
seas  of  past  geological  ages,  and  by  comparing  the  nature  and 
position  of  their  fossil  remains  with  those  of  living  marine  faunae, 
he  measured  the  depths  of  the  water  along  their  shores.  He  col 
lected  a  vast  amount  of  material,  and  the  results  of  his  labors 
have  formed  the  basis  of  all  subsequent  generalizations  upon  this 
subject.  Nevertheless  he  arrived  at  some  erroneous  conclusions, 
which,  had  he  lived,  he  would  no  doubt  have  been  the  first  to 
correct.  Dredging  from  low-water-mark  outward,  he  found  that, 
from  the  Laminarian  and  Coralline  zone,  the  animals  began  grad 
ually  to  decrease  in  number,  and  that,  at  a  depth  of  two  or  three 
hundred  fathoms,  the  dredge  always  came  up  nearly  empty. 
He  inferred  that  at  a  certain  depth  the  weight  of  water  became 
too  great  to  be  endured  by  animals,  and  that  the  ocean  beyond 
this  line,  like  the  land  beyond  the  line  of  perpetual  snow,  was 
barren  of  life.  This  result  seemed  the  more  probable  on  account 
of  the  immense  pressure  to  which  animals  are  subjected,  even  at 
a  comparatively  moderate  depth.  A  column  of  water  thirty-two 
feet  high  is  equal  to  one  atmosphere  in  weight ;  this  pressure 
being  increased  to  the  same  amount  for  every  thirty-two  feet  of 
depth,  it  follows  that  a  fish  one  hundred  and  twenty-eight  feet,  or 
some  twenty  fathoms  below  the  surface,  is  under  the  pressure  of 
almost  four  atmospheres  plus  that  of  the  air  outside.  Wherever 
tides  run  high,  as  in  the  Bay  of  Fundy,  for  instance,  where  an 
animal  is  under  the  pressure  of  one  atmosphere  at  low  tide,  and 
of  three  atmospheres  at  high  tide,  we  see  that  marine  animals  are 
uninjured  by  great  changes  of  pressure.  Yet  it  seems  natural  to 
suppose  that  there  is  a  limit  to  this  power  of  resistance  ;  and 
that  there  must  exist  barren  areas  at  the  bottom  of  the  ocean,  as 
destitute  of  life  as  the  regions  on  the  earth  which  are  above  the 
line  of  perpetual  snow.  No  doubt  pressure  does  influence  the 
distribution  of  life  in  the  ocean ;  but  it  would  seem,  from  subse 
quent  observations,  that  the  boundaries  assigned  by  Forbes  were 
far  too  narrow,  and  that  the  structure  of  many  marine  animals 


DISTRIBUTION    OF   LIFE    IN   THE    OCEAN.  151 

enables  them  to  live  under  a  weight,  the  one  hundredth  part  of 
which  would  be  fatal  to  any  terrestrial  animal. 

For  some  years  Forbes's  theory  was  very  generally  accepted, 
and  the  results  of  Darwin's  and  Dana's  investigations,  showing  that 
corals  could  not  live  beyond  a  depth  of  fifteen  fathoms,  §eemed  to 
confirm  it.  But,  quite  recently,  facts  derived  from  new  and 
unlocked  for  sources  of  information  have  given  a  check  to  this 
theory.  Practical  objects,  the  interests  of  commerce  have  come 
to  the  aid  of  science  (rewarding  her  for  the  gift  first  received  at 
her  hands),  and  the  telegraph  cables,  alive  with  the  secrets  of  sea 
and  land,  have  brought  us  tidings  from  the  deep.  In  the  Medi 
terranean  and  in  the  Red  Sea,  from  depths  of  eighteen  hundred 
to  two  thousand  fathoms,  living  animals  have  been  brought  up  on 
the  telegraph  wires,  not  of  doubtful  infusorial  character,  hovering 
on  the  border-land  between  animal  and  vegetable  life,  but  of  con 
siderable  size,  as  for  instance,  one  or  two  kinds  of  Crustacea, 
Cockles,  stocks  of  Bryozoa  and  tubes  of  Annelids.  When  the 
cable  between  France  and  Algiers  was  taken  up  from  a  depth  of 
eighteen  hundred  fathoms,  there  came  with  it  an  Oyster,  Cockle 
shells,  Annelid  tubes,  Bryozoa  and  Sea-fans.  As  these  animals 
were  growing  upon  it,  there  could  be  no  doubt  that  they  had 
their  normal  life  and  development  at  this  depth,  and  since  they 
are  carnivorous,  they  tell  also  of  the  existence  of  other  animals 
with  them  on  which  they  feed.  This  discovery  alone  shows  how 
much  yet  remains  to  be  done  before  we  shall  fully  understand 
the  laws  of  marine  life.  But  we  already  have  ample  evidence 
that  the  same  beneficent  order  controls  the  distribution  of  ani 
mals  in  the  ocean  as  on  land,  appointing  to  all  its  inhabitants 
their  fitting  home  in  the  dim  waste  of  waters. 


SYSTEMATIC    TABLE 


OF    THE    ANIMALS    DESCRIBED    IN    THIS   VOLUME. 


RADIATA. 


CLASS    I. -POLYPI. 


ORDER  I.  —  ACTINARIA  EDW. 

Metridium  marginatum  EDW. 
Rhodactinia  Davisii  AG. 
Bicidium  parasiticum  AG. 
Arachnactis  brachiolata  A.  AG. 
Halcampa  albida  AG. 


ORDER  H.  —  M ADREPORI A  AG. 

Astrangia  Dance  AG. 

ORDER  HI.— HALC  F  ONARIA  EDW. 

Halcyonium  carneum  AG. 


CLASS   II.  — ACALEPHJE. 


ORDER  I.  — HYDROIDEA  JOHNST. 

Velella  mutica  Bosc. 
Physalia  Arethusa  TIL. 
Nanomia  cam  A.  AG. 
Millepora  alcicornis  LIN. 
Hydractinia  polydina  AG. 
Tubularia  Couthouyi  AG. 
Hybocodon  prolifer  AG. 
Coryne  mirabUis  AG. 
Turris  vesicaria  A.  AG. 
Bougainvillia  superciliaris  AG. 
Dysmorphosa  fulgurans  A.  AG. 
Dynamena  pumila  LAMX. 
Dyphasia  rosacea  AG. 
Lafcea  cornuta  LAMX. 
Melicertum  carnja^ffula  PER.  et  LES. 
Ptychogena  laciea  A.  AG. 
Laomedea  amphora  AG. 


Zygodactyla  groenlandica  AG. 
Tima  formosa  AG. 
Eucope  diaphana  AG. 
Clytia  bicophora  AG. 
Oceania  languida  A.  AG. 

ORDER  H.  —  DISCOPHOR^E  ESCH. 

Halyclistus  auricula,  CLARKE. 
Trachynema  digitate  A.  AG. 
Campanella  pachyderma  A.  AG. 
Cyanea  arctica  PER.  et.  LES. 
Aurelia  flavidula  PER.  et  LES. 

ORDER  HI.— CTENOPHOR^E  ESCH. 

Idyia  roseola  AG. 
Pleurobrachia  rhododactyla  AG. 
Bolina  alata  AG. 


SYSTEMATIC    TABLE. 


153 


CLASS   III.  — ECHINODEBMATA. 


ORDER  I.  —  CRINOIDEA. 

Pentacrinus. 

Alecto  EschricMi  M.  &  T. 

Alec  to  meridionalis  AG. 

ORDER  H.  —  OPHIURIDEA. 

Amphiura  squamata  SARS. 
Ophiopholis  bellis  LYM. 
Astrophyton  Agassizii  STIMP. 

ORDER  III.  —  ASTERIDEA. 

Ctenodixcus  cr'ispatus  D.  &  K. 
Hippasteria  pliryglana  AG. 
Cribrella  oculata  FORBES. 


Solaster  endeca  FORBES. 
Crossaster  papposa  M.  &  T. 
Astracanthion  pallid  us  AG. 
Astracantldon  berylinus  AG. 

ORDER  IV.  —  ECHINIDE.A. 

Toxopneustes  drobacJiiensis  AG. 
Echinarachnius  parma  GRAY. 

ORDER  V.  — HOLOTHURIDEA. 

Caudina  arenata  STIMP. 
Synapta  tennis  AYRES. 
Cuvieria  squamata  D.  &  K. 
Pentacta  frondosa,  JAG. 


20 


INDEX. 


PAGE 

Acalephs,  21 

Actinia,  7 

Actinoids,  7 

Alecto  Eschriclitii,  121 

Alecto  meridionalis,  121 

Amphiura  squamata,  115 

Arachnactis  brachiolata,  14 

Astracanthion  berylinus,  108 

Astracanthion  pallidus,  112 

Astrangia  Danse,  16 

Astrophyton  Agassizii,  117 

Aurelia  flavidula,  42 

Bicidium  parasitieum,  15 

Bolina  alata,  31 

Bougainvillia  superciliaris,  69 

Campanella  pachyderma,  44 

Campanularians,  49 

Caudina  arenata,  97 

Circe,  45 

Clytia  bicophora,  56 

Comatula,  121 

Coryne  mirabilis,  68 

Cribrella  oculata,  1 1 2 

Crinoids,  120 

Crossaster  papposa,  114 

Ctenodiscus  crispatus,  113 

Ctenophoras,  26 

Cuvieria  squamata,  98 

Cyanea  arctica,  38 
Development  of  Melicertum,          64 

"           "      Tima,  64 

Discophorae,  3  7 
Distribution  of  Life  in  the 

Ocean,  141 

Dynamena  pumila,  66 


PAGE 

Dyphasia  rosacea,  67 

Dysmorphosa  fulgurans,  75 

Echinarachnius  parma,  106 

Echinoderms,  91 

Echinoids,  101 

Embryology  of  Astracanthion,  124 

"            "     Ctenophorae,  34 

"            "     Echinoderms,  123 

"            "     Ophiurans,  135 

"            "     Sea-urchins,  130 

"            "     Star-fishes,  124 

Eucope  diaphana,  30 

Halcampa  albida,  16 

Haley onium  carneum,  19 

Halcyonoids,  1 9 

Halyclistus  aurirula,  46 

Hippasteria  phrygiana,  113 

Holothurians,  95 

Hybocodon  prolifer,  74 

Hydractinia  polyclina,  73 

Hydroids,  49 

Idyia  roseola,  32 

Lafoea  cornuta,  67 

Laomedea  amphora,  65 

Lucernaria,  46 

Madreporians,  1 6 

Melicertum  campanula,  63 

Metridium  marginatum,  7 

Millepora  alcicornis,  22 

Mode  of  catching  Jelly-fishes,  85 

Nanomia  cara,  76 

Oceania  languida,  53 

Ophiurans,  115 

Ophiopholis  bellis,  1 1 5 

Pentacrinus,  121 


Pentacta  frondosa, 

Pleurobrachia  rhododactyla, 

Polyps, 

Ptychogena  lactea, 

Physalia  Arethusa, 

Radiates, 

Rhodactinia  Davisii, 

Sarsia, 

Sea-urchin, 

Sertularians, 

Solaster  endeca, 


INDEX.  155 

99  Star-fishes,  108 

27  Synapta  tenuis,  95 

5  Systematic  Table,  152 

86  Tima  formosa,  60 

83  Toxopneustes  drobachiensis,  101 

1  Trachynema  digitale,  45 

13  Tubularia  Couthouyi,  72 

68  Tubularians,  67 

101  Turris  vesicaria,  69 

66  Velella  mutica,  84 

114  Zygodactyla  groenlandica,  57 


THE  END. 


Cambridge  :  Stereotyped  and  Printed  by  Welch,  Bigelow,  &  Co. 


Agassiz. 

Sea  side  studies* 


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